1
|
Tan BH, Ahemad N, Pan Y, Ong CE. Mechanism-based inactivation of cytochromes P450: implications in drug interactions and pharmacotherapy. Xenobiotica 2024:1-24. [PMID: 39175333 DOI: 10.1080/00498254.2024.2395557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 08/17/2024] [Accepted: 08/19/2024] [Indexed: 08/24/2024]
Abstract
Cytochrome P40 (CYP) enzymes dominate the metabolism of numerous endogenous and xenobiotic substances. While it is commonly believed that CYP-catalysed reactions result in the detoxication of foreign substances, these reactions can also yield reactive intermediates that can bind to cellular macromolecules to cause cytotoxicity or irreversibly inactivate CYPs that create them.Mechanism-based inactivation (MBI) produces either irreversible or quasi-irreversible inactivation and is commonly caused by CYP metabolic bioactivation to an electrophilic reactive intermediate. Many drugs that have been known to cause MBI in CYPs have been discovered as perpetrators in drug-drug interactions throughout the last 20-30 years.This review will highlight the key findings from the recent literature about the mechanisms of CYP enzyme inhibition, with a focus on the broad mechanistic elements of MBI for widely used drugs linked to the phenomenon. There will also be a brief discussion of the clinical or pharmacokinetic consequences of CYP inactivation with regard to drug interaction and toxicity risk.Gaining knowledge about the selective inactivation of CYPs by common therapeutic drugs helps with the assessment of factors that affect the systemic clearance of co-administered drugs and improves comprehension of anticipated interactions with other drugs or xenobiotics.
Collapse
Affiliation(s)
- Boon Hooi Tan
- Division of Applied Biomedical Sciences and Biotechnology, International Medical University, Kuala Lumpur, Malaysia
| | - Nafees Ahemad
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, Selangor, Malaysia
| | - Yan Pan
- Department of Biomedical Science, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia
| | - Chin Eng Ong
- School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| |
Collapse
|
2
|
Ilipilla G, Arnold LE. The role of adrenergic neurotransmitter reuptake inhibitors in the ADHD armamentarium. Expert Opin Pharmacother 2024; 25:945-956. [PMID: 38900676 DOI: 10.1080/14656566.2024.2369197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/13/2024] [Indexed: 06/22/2024]
Abstract
INTRODUCTION Adrenergic neurotransmitter reuptake inhibitors are gaining attention in treatment for attention-deficit hyperactivity disorder (ADHD). Due to their effects on norepinephrine, dopamine, and serotonin neurotransmission, they benefit both ADHD and comorbid disorders and have some other advantages including longer duration of action and fewer adverse effects compared to stimulants. There is continued interest in these agents with novel mechanisms of action in treatment of ADHD. AREAS COVERED The authors conducted a PubMed literature search using the following key words: 'ADHD' AND 'adrenergic reuptake inhibitors' OR 'nonstimulants' OR 'atomoxetine' OR 'Viloxazine' OR 'Dasotraline' OR 'Centanafadine' OR 'PDC-1421' OR 'Reboxetine' OR 'Edivoxetine' OR 'Bupropion' OR 'Venlafaxine' OR 'Duloxetine.' They reviewed FDA fact sheets of available medications for safety/tolerability studies and reviewed published clinical studies of these medications for treatment of ADHD. EXPERT OPINION Adrenergic neurotransmitter reuptake inhibitors fit the diverse needs of children and adolescents with ADHD with 1) poor tolerability to stimulants (e.g. due to growth suppression, insomnia, rebound irritability, co-morbid depression, anxiety and tic disorders, substance abuse or diversion concerns), 2) cardiac risks, and/or 3) need for extended duration of action. Their differences in receptor affinities and modulating effects support the unique benefits of individual agents.
Collapse
Affiliation(s)
- Geeta Ilipilla
- Department of Psychiatry and Behavioral Health, Nationwide Childrens Hospital, Columbus, OH, USA
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Health, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - L Eugene Arnold
- Department of Psychiatry and Behavioral Health, Nisonger Center Clinical Trials Program, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| |
Collapse
|
3
|
Guo HL, Wu DD, Fu D, Li Y, Wang J, Zhang YY, Wang WJ, Huang J, Fang WR, Xu J, Hu YH, Liu QQ, Chen F. Individualized atomoxetine response and tolerability in children with ADHD receiving different dosage regimens: the need for CYP2D6 genotyping and therapeutic drug monitoring to dance together. Transl Psychiatry 2024; 14:151. [PMID: 38504095 PMCID: PMC10951231 DOI: 10.1038/s41398-024-02859-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/21/2024] Open
Abstract
Integrating CYP2D6 genotyping and therapeutic drug monitoring (TDM) is crucial for guiding individualized atomoxetine therapy in children with attention-deficit/hyperactivity disorder (ADHD). The aim of this retrospective study was (1) to investigate the link between the efficacy and tolerability of atomoxetine in children with ADHD and plasma atomoxetine concentrations based on their CYP2D6 genotypes; (2) to offer TDM reference range recommendations for atomoxetine based on the CYP2D6 genotypes of children receiving different dosage regimens. This retrospective study covered children and adolescents with ADHD between the ages of 6 and <18, who visited the psychological and behavioral clinic of Children's Hospital of Nanjing Medical University from June 1, 2021, to January 31, 2023. The demographic information and laboratory examination data, including CYP2D6 genotype tests and routine TDM of atomoxetine were obtained from the hospital information system. We used univariate analysis, Mann-Whitney U nonparametric test, Kruskal-Wallis test, and the receiver operating characteristic (ROC) curve to investigate outcomes of interest. 515 plasma atomoxetine concentrations of 385 children (325 boys and 60 girls) with ADHD between 6 and 16 years of age were included for statistical analysis in this study. Based on genotyping results, >60% of enrolled children belonged to the CYP2D6 extensive metabolizer (EM), while <40% fell into the intermediate metabolizer (IM). CYP2D6 IMs exhibited higher dose-corrected plasma atomoxetine concentrations by 1.4-2.2 folds than those CYP2D6 EMs. Moreover, CYP2D6 IMs exhibited a higher response rate compare to EMs (93.55% vs 85.71%, P = 0.0132), with higher peak plasma atomoxetine concentrations by 1.67 times than those of EMs. Further ROC analysis revealed that individuals under once daily in the morning (q.m.) dosing regimen exhibited a more effective response to atomoxetine when their levels were ≥ 268 ng/mL (AUC = 0.710, P < 0.001). In addition, CYP2D6 IMs receiving q.m. dosing of atomoxetine were more likely to experience adverse reactions in the central nervous system and gastrointestinal system when plasma atomoxetine concentrations reach 465 and 509 ng/mL, respectively. The findings in this study provided promising treatment strategy for Chinese children with ADHD based on their CYP2D6 genotypes and plasma atomoxetine concentration monitoring. A peak plasma atomoxetine concentration higher than 268 ng/mL might be requisite for q.m. dosing. Assuredly, to validate and reinforce these initial findings, it is necessary to collect further data in controlled studies with a larger sample size.
Collapse
Affiliation(s)
- Hong-Li Guo
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Dan-Dan Wu
- Department of Children Health Care, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Di Fu
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
- Visiting graduate student from China Pharmaceutical University, Nanjing, China
| | - Yue Li
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jie Wang
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yuan-Yuan Zhang
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Wei-Jun Wang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
- Visiting graduate student from China Pharmaceutical University, Nanjing, China
| | - Jian Huang
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Wei-Rong Fang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Xu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ya-Hui Hu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China.
| | - Qian-Qi Liu
- Department of Children Health Care, Children's Hospital of Nanjing Medical University, Nanjing, China.
| | - Feng Chen
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing, China.
| |
Collapse
|
4
|
Personalizing atomoxetine dosing in children with ADHD: what can we learn from current supporting evidence. Eur J Clin Pharmacol 2023; 79:349-370. [PMID: 36645468 DOI: 10.1007/s00228-022-03449-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/20/2022] [Indexed: 01/17/2023]
Abstract
PURPOSE There is marked heterogeneity in treatment response of atomoxetine in patients with attention deficit/hyperactivity disorder (ADHD), especially for the pediatric population. This review aims to evaluate current evidence to characterize the dose-exposure relationship, establish clinically relevant metrics for systemic exposure to atomoxetine, define a therapeutic exposure range, and to provide a dose-adaptation strategy before implementing personalized dosing for atomoxetine in children with ADHD. METHODS A comprehensive search was performed across electronic databases (PubMed and Embase) covering the period of January 1, 1985 to July 10, 2022, to summarize recent advances in the pharmacokinetics, pharmacogenomics/pharmacogenetics (PGx), therapeutic drug monitoring (TDM), physiologically based pharmacokinetics (PBPK), and population pharmacokinetics (PPK) of atomoxetine in children with ADHD. RESULTS Some factors affecting the pharmacokinetics of atomoxetine were summarized, including food, CYP2D6 and CYP2C19 phenotypes, and drug‒drug interactions (DDIs). The association between treatment response and genetic polymorphisms of genes encoding pharmacological targets, such as norepinephrine transporter (NET/SLC6A2) and dopamine β hydroxylase (DBH), was also discussed. Based on well-developed and validated assays for monitoring plasma concentrations of atomoxetine, the therapeutic reference range in pediatric patients with ADHD proposed by several studies was summarized. However, supporting evidence on the relationship between systemic atomoxetine exposure levels and clinical response was far from sufficient. CONCLUSION Personalizing atomoxetine dosage may be even more complex than anticipated thus far, but elucidating the best way to tailor the non-stimulant to a patient's individual need will be achieved by combining two strategies: detailed research in linking the pharmacokinetics and pharmacodynamics in pediatric patients, and better understanding in nature and causes of ADHD, as well as environmental stressors.
Collapse
|
5
|
Physiologically Based Pharmacokinetic Modeling to Describe the CYP2D6 Activity Score-Dependent Metabolism of Paroxetine, Atomoxetine and Risperidone. Pharmaceutics 2022; 14:pharmaceutics14081734. [PMID: 36015360 PMCID: PMC9414337 DOI: 10.3390/pharmaceutics14081734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/12/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
The cytochrome P450 2D6 (CYP2D6) genotype is the single most important determinant of CYP2D6 activity as well as interindividual and interpopulation variability in CYP2D6 activity. Here, the CYP2D6 activity score provides an established tool to categorize the large number of CYP2D6 alleles by activity and facilitates the process of genotype-to-phenotype translation. Compared to the broad traditional phenotype categories, the CYP2D6 activity score additionally serves as a superior scale of CYP2D6 activity due to its finer graduation. Physiologically based pharmacokinetic (PBPK) models have been successfully used to describe and predict the activity score-dependent metabolism of CYP2D6 substrates. This study aimed to describe CYP2D6 drug–gene interactions (DGIs) of important CYP2D6 substrates paroxetine, atomoxetine and risperidone by developing a substrate-independent approach to model their activity score-dependent metabolism. The models were developed in PK-Sim®, using a total of 57 plasma concentration–time profiles, and showed good performance, especially in DGI scenarios where 10/12, 5/5 and 7/7 of DGI AUClast ratios and 9/12, 5/5 and 7/7 of DGI Cmax ratios were within the prediction success limits. Finally, the models were used to predict their compound’s exposure for different CYP2D6 activity scores during steady state. Here, predicted DGI AUCss ratios were 3.4, 13.6 and 2.0 (poor metabolizers; activity score = 0) and 0.2, 0.5 and 0.95 (ultrarapid metabolizers; activity score = 3) for paroxetine, atomoxetine and risperidone active moiety (risperidone + 9-hydroxyrisperidone), respectively.
Collapse
|
6
|
Ruppert K, Geffert C, Clement HW, Bachmann C, Haberhausen M, Schulz E, Fleischhaker C, Biscaldi-Schäfer M. Therapeutic drug monitoring of atomoxetine in children and adolescents with attention-deficit/ hyperactivity disorder: a naturalistic study. J Neural Transm (Vienna) 2022; 129:945-959. [PMID: 35391568 PMCID: PMC9217867 DOI: 10.1007/s00702-022-02483-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 02/22/2022] [Indexed: 12/02/2022]
Abstract
The selective norepinephrine reuptake inhibitor atomoxetine is potentially among the first-line pharmacotherapy options for ADHD. Therapeutic drug monitoring (TDM) with the quantification and interpretation of atomoxetine serum concentrations is used to determine an individual dose followed by an optimal effectiveness and minimal side effects. The aim of this retrospective pharmacokinetic–pharmacodynamic analysis was to derive age-appropriate recommendations for the implementation of TDM to improve the efficacy and tolerability of atomoxetine in children and adolescents. Using the analytical method of high-performance liquid chromatography with UV detection, 94 serum concentrations of 74 patients between 6 and 21 years of age were determined. Therapeutic effectiveness and side effects were evaluated according to the categories “low”, “moderate”, and “significant”. As part of TDM, a time interval with maximum concentrations of 1–3 h after the administration of atomoxetine was determined for blood sampling. In this time interval, a significant correlation between the weight-normalized dose and the serum concentrations was found. The efficacy as well as the tolerability proved to be mainly moderate or significant. A preliminary therapeutic reference range was between 100 and 400 ng/ml. Naturalistic studies have limitations. Therefore, and due to a limited study population, the results have to be regarded as preliminary observations that must be confirmed in further studies. The preliminary therapeutic reference range for children and adolescents proved to be narrower than the reference range for adult patients. However, due to good efficacy and tolerability an exact reference range remained difficult to determine.
Collapse
Affiliation(s)
- Katrin Ruppert
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | | | - Hans-Willi Clement
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Christian Bachmann
- Department of Child and Adolescent Psychiatry, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Ulm, Ulm, Germany
| | - Michael Haberhausen
- Department of Child and Adolescent Psychiatry, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
| | - Eberhard Schulz
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Christian Fleischhaker
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
| | - Monica Biscaldi-Schäfer
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| |
Collapse
|
7
|
Individualization of attention-deficit/hyperactivity disorder treatment: pharmacotherapy considerations by age and co-occurring conditions. CNS Spectr 2021; 26:202-221. [PMID: 32054558 DOI: 10.1017/s1092852919001822] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that manifests in childhood and can persist into adolescence and adulthood. Impairments associated with ADHD can impact quality of life, social interactions, and increase the risk of morbidity and mortality; however, for many patients, effective treatment can lessen these effects. Pharmacotherapy with stimulants or nonstimulants is recommended in conjunction with psychosocial therapy for most patients. Determining the optimal pharmacotherapy can be complex, and the clinician needs to consider many factors such as the patient's age, comorbidities, and lifestyle. Furthermore, the needs of the patient with ADHD will change over time, with specific challenges to consider at each stage of life. A variety of Food and Drug Administration (FDA)-approved stimulant and nonstimulant formulations are available with different modes of delivery and durations of effect. This armamentarium of ADHD medications can be used to individualize ADHD treatment for each patient's needs. This article combines current information from the literature and the first-hand experience of the authors to provide guidance on ADHD treatment options for patients of different ages and for some of the more common comorbidities.
Collapse
|
8
|
Lifetime evolution of ADHD treatment. J Neural Transm (Vienna) 2021; 128:1085-1098. [PMID: 33993352 DOI: 10.1007/s00702-021-02336-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD), has been traditionally considered a neurodevelopmental disorder affecting children and adolescents characterized by inattention, hyperactivity, disruptive behavior, and impulsivity. Although still debated, it is evident that ADHD is also present in adulthood, but this diagnosis is rarely carried out, mainly for the frequent comorbidity with other psychiatric and/or substance abuse disorders. Given the need to shed more light on the pharmacological treatment of ADHD, we performed a naturalistic review to review and comment on the available literature of ADHD treatment across the lifespan. Indeed, stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants, although requiring some weeks to be fully effective, are useful when a substance abuse history is detected. In any case, the pharmacological management of ADHD appears to be still largely influenced by the individual experience of the clinicians. Further longitudinal studies with a careful and detailed characterization of participants across different phases of the lifespan are also required to provide relevant confirmations (or denials) regarding pharmacological treatments amongst the different age groups.
Collapse
|
9
|
Wang Z, Kosheleff AR, Adeojo LW, Odebo O, Adewole T, Qin P, Maletic V, Schwabe S, Nasser A. Impact of Paroxetine, a Strong CYP2D6 Inhibitor, on SPN-812 (Viloxazine Extended-Release) Pharmacokinetics in Healthy Adults. Clin Pharmacol Drug Dev 2021; 10:1365-1374. [PMID: 33943033 PMCID: PMC8597116 DOI: 10.1002/cpdd.948] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/10/2021] [Indexed: 01/18/2023]
Abstract
SPN‐812 (viloxazine extended‐release) is a novel nonstimulant recently approved as a treatment for attention‐deficit/hyperactivity disorder in children and adolescents. Given that SPN‐812 is metabolized by CYP2D6 and may be coadministered with CYP2D6 inhibitors, this trial investigated the pharmacokinetics and safety of SPN‐812 coadministered with the potent CYP2D6 inhibitor paroxetine. In this single‐sequence, 3‐treatment period study in healthy volunteers, subjects received a single oral dose of 700 mg SPN‐812 alone (period 1), 20 mg daily paroxetine (10 days, period 2), followed by concurrent administration of SPN‐812 and paroxetine (period 3). Blood samples were collected for 72 hours post‐SPN‐812 dosing and analyzed for viloxazine and its primary metabolite, 5‐HVLX‐gluc. Twenty‐two healthy adults were enrolled; all completed the trial. The potential for drug interaction between SPN‐812 and paroxetine was assessed using analysis of variance on the log‐transformed pharmacokinetic parameters Cmax, AUC0‐t, and AUCinf. The least‐squares geometric mean ratios for viloxazine were (reported as the ratio of combination/SPN‐812 alone) Cmax, 116.04%; 90%CI, 109.49%‐122.99%; AUC0‐t, 134.65%; 90%CI, 127.65‐142.03; and AUCinf, 134.80%; 90%CI, 127.94%‐142.03%. CYP2D6 inhibition resulted in a modest change (<35%) on viloxazine AUCs with no change in Cmax. All adverse events were mild in severity.
Collapse
Affiliation(s)
- Zhao Wang
- Supernus Pharmaceuticals, Inc., Rockville, Maryland, USA
| | | | | | | | - Toyin Adewole
- Supernus Pharmaceuticals, Inc., Rockville, Maryland, USA
| | - Peibing Qin
- Supernus Pharmaceuticals, Inc., Rockville, Maryland, USA
| | - Vladimir Maletic
- Department of Psychiatry/Behavioral Science, University of South Carolina School of Medicine, Greenville, South Carolina, USA
| | - Stefan Schwabe
- Supernus Pharmaceuticals, Inc., Rockville, Maryland, USA
| | - Azmi Nasser
- Supernus Pharmaceuticals, Inc., Rockville, Maryland, USA
| |
Collapse
|
10
|
Park D, Mabunga DFN, Adil KJ, Ryu O, Valencia S, Kim R, Kim HJ, Cheong JH, Kwon KJ, Kim HY, Han SH, Jeon SJ, Shin CY. Synergistic efficacy and diminished adverse effect profile of composite treatment of several ADHD medications. Neuropharmacology 2021; 187:108494. [PMID: 33587920 DOI: 10.1016/j.neuropharm.2021.108494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 01/05/2021] [Accepted: 02/07/2021] [Indexed: 11/26/2022]
Abstract
Although attention-deficit/hyperactivity disorder (ADHD) is widely studied, problems regarding the adverse effect risks and non-responder problems still need to be addressed. Combination pharmacotherapy using standard dose regimens of existing medication is currently being practiced mainly to augment the therapeutic efficacy of each drug. The idea of combining different pharmacotherapies with different molecular targets to alleviate the symptoms of ADHD and its comorbidities requires scientific evidence, necessitating the investigation of their therapeutic efficacy and the mechanisms underlying the professed synergistic effects. Here, we injected male ICR mice with MK-801 to induce ADHD behavioral condition. We then modeled a "combined drug" using sub-optimal doses of methylphenidate, atomoxetine, and fluoxetine and investigated the combined treatment effects in MK-801-treated mice. No sub-optimal dose monotherapy alleviated ADHD behavioral condition in MK-801-treated mice. However, treatment with the combined drug attenuated the impaired behavior of MK-801-treated animals. Growth impediment, sleep disturbances, or risk of substance abuse were not observed in mice treated subchronically with the combined drugs. Finally, we observed that the combined ADHD drug rescued alterations in p-AKT and p-ERK1/2 levels in the prefrontal cortex and hippocampus, respectively, of MK-801-treated mice. Our results provide experimental evidence of a possible new pharmacotherapy option in ameliorating the ADHD behavioral condition without the expected adverse effects. The detailed mechanism of action underlying the synergistic therapeutic efficacy and reduced adverse reaction by combinatorial drug treatment should be investigated further in future studies.
Collapse
Affiliation(s)
- Donghyun Park
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Darine Froy N Mabunga
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Keremkleroo Jym Adil
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Onjeon Ryu
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Schley Valencia
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Ryeongeun Kim
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Hee Jin Kim
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, 815 Hwarangro, Nowon-gu, Seoul, 01795, Republic of Korea
| | - Jae Hoon Cheong
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, 815 Hwarangro, Nowon-gu, Seoul, 01795, Republic of Korea
| | - Kyung Ja Kwon
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Hahn Young Kim
- Department of Neurology, Konkuk University Medical Center, Center for Geriatric Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, 05029, Republic of Korea
| | - Seol-Heui Han
- Department of Neurology, Konkuk University Medical Center, Center for Geriatric Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, 05029, Republic of Korea
| | - Se Jin Jeon
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea; TriNeuro Inc., 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea.
| | - Chan Young Shin
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea; TriNeuro Inc., 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea.
| |
Collapse
|
11
|
Jung EH, Lee YJ, Kim DH, Kang P, Lim CW, Cho CK, Jang CG, Lee SY, Bae JW. Effects of paroxetine on the pharmacokinetics of atomoxetine and its metabolites in different CYP2D6 genotypes. Arch Pharm Res 2020; 43:1356-1363. [PMID: 33245517 DOI: 10.1007/s12272-020-01300-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022]
Abstract
The aim of this study was to investigate the effects of paroxetine, a potent inhibitor of CYP2D6, on the pharmacokinetics of atomoxetine and its two metabolites, 4-hydroxyatomoxetine and N-desmethylatomoxetine, in different CYP2D6 genotypes. Twenty-six healthy subjects were recruited and divided into CYP2D6*wt/*wt (*wt=*1 or *2, n = 10), CYP2D6*wt/*10 (n = 9), and CYP2D6*10/*10 groups (n = 7). In atomoxetine phase, all subjects received a single oral dose of atomoxetine (20 mg). In paroxetine phase, after administration of a single oral dose of paroxetine (20 mg) for six consecutive days, all subjects received a single oral dose of atomoxetine with paroxetine. Plasma concentrations of atomoxetine and its metabolites were determined up to 24 h after dosing. During atomoxetine phase, there were significant differences in Cmax and AUC0-24 of atomoxetine and N-desmethylatomoxetine among three genotype groups, whereas significant differences were not found in relation to CYP2D6*10 allele after administration of paroxetine. AUC ratios of 4-hydroxyatomoxetine and N-desmethylatomoxetine to atomoxetine were significantly different among three genotype groups during atomoxetine phase (all, P < 0.001), but after paroxetine treatment significant differences were not found. After paroxetine treatment, AUC0-24 of atomoxetine was increased by 2.3-, 1.7-, and 1.3-fold, in CYP2D6*wt/*wt, CYP2D6*wt/*10, and CYP2D6*10/*10 groups in comparison to atomoxetine phase, respectively. AUC ratio of 4-hydroxyatomoxetine to atomoxetine in each group was significantly decreased, whereas AUC ratio of N-desmethylatomoxetine to atomoxetine significantly increased after administration of paroxetine. In conclusion, paroxetine coadministration significantly affected pharmacokinetic parameters of atomoxetine and its two metabolites, 4-hydroxyatomoxetine and N-desmethylatomoxetine. When atomoxetine was administered alone, Cmax, AUC0-24 and CL/F of atomoxetine were significantly different among the three CYP2D6 genotype groups. However, after paroxetine coadministration, no significant differences in these pharmacokinetic parameters were observed among the CYP2D6 genotype groups.
Collapse
Affiliation(s)
- Eui Hyun Jung
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Yun Jeong Lee
- College of Pharmacy, Dankook University, Cheonan, 31116, Republic of Korea
| | - Dong-Hyun Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Pureum Kang
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Chang Woo Lim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Chang-Keun Cho
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Choon-Gon Jang
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Seok-Yong Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Jung-Woo Bae
- College of Pharmacy, Keimyung University, Daegu, 42601, Republic of Korea.
| |
Collapse
|
12
|
Protti M, Mandrioli R, Marasca C, Cavalli A, Serretti A, Mercolini L. New‐generation, non‐SSRI antidepressants: Drug‐drug interactions and therapeutic drug monitoring. Part 2: NaSSAs, NRIs, SNDRIs, MASSAs, NDRIs, and others. Med Res Rev 2020; 40:1794-1832. [DOI: 10.1002/med.21671] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/18/2020] [Accepted: 03/29/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Michele Protti
- Department of Pharmacy and Biotechnology (FaBiT), Pharmaco‐Toxicological Analysis Laboratory (PTA Lab)Alma Mater Studiorum ‐ University of Bologna Bologna Italy
| | - Roberto Mandrioli
- Department for Life Quality Studies (QuVi)Alma Mater Studiorum ‐ University of BolognaRimini Italy
| | - Camilla Marasca
- Department of Pharmacy and Biotechnology (FaBiT), Pharmaco‐Toxicological Analysis Laboratory (PTA Lab)Alma Mater Studiorum ‐ University of Bologna Bologna Italy
- Computational and Chemical BiologyFondazione Istituto Italiano di Tecnologia (IIT) Genoa Italy
| | - Andrea Cavalli
- Department of Pharmacy and Biotechnology (FaBiT), Pharmaco‐Toxicological Analysis Laboratory (PTA Lab)Alma Mater Studiorum ‐ University of Bologna Bologna Italy
- Computational and Chemical BiologyFondazione Istituto Italiano di Tecnologia (IIT) Genoa Italy
| | - Alessandro Serretti
- Department of Biomedical and Neuromotor Sciences (DIBINEM)Alma Mater Studiorum ‐ University of Bologna Bologna Italy
| | - Laura Mercolini
- Department of Pharmacy and Biotechnology (FaBiT), Pharmaco‐Toxicological Analysis Laboratory (PTA Lab)Alma Mater Studiorum ‐ University of Bologna Bologna Italy
| |
Collapse
|
13
|
Mucci F, Avella MT, Marazziti D. ADHD with Comorbid Bipolar Disorders: A Systematic Review of Neurobiological, Clinical and Pharmacological Aspects Across the Lifespan. Curr Med Chem 2020; 26:6942-6969. [PMID: 31385763 DOI: 10.2174/0929867326666190805153610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/05/2018] [Accepted: 11/15/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Attention deficit hyperactivity (ADHD) disorder is a neurodevelopmental disorder characterized by inattention, hyperactivity, disruptive behaviour, and impulsivity. Despite considered typical of children for a long time, the persistence of ADHD symptoms in adulthood gained increasing interest during the last decades. Indeed, its diagnosis, albeit controversial, is rarely carried out even because ADHD is often comorbid with several other psychiatric diosrders, in particular with bipolar disorders (BDs), a condition that complicates the clinical picture, assessment and treatment. AIMS The aim of this paper was to systematically review the scientific literature on the neurobiological, clinical features and current pharmacological management of ADHD comorbid with BDs across the entire lifespan, with a major focus on the adulthood. DISCUSSION The pharmacology of ADHD-BD in adults is still empirical and influenced by the individual experience of the clinicians. Stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants are useful when a substance abuse history is detected, although they require some weeks in order to be fully effective. In any case, an in-depth diagnostic and clinical evaluation of the single individual is mandatory. CONCLUSION The comorbidity of ADHD with BD is still a controversial matter, as it is the notion of adult ADHD as a distinct nosological category. Indeed, some findings highlighted the presence of common neurobiological mechanisms and overlapping clinical features, although disagreement does exist. In any case, while expecting to disentangle this crucial question, a correct management of this comorbidity is essential, which requires the co-administration of mood stabilizers. Further controlled clinical studies in large samples of adult ADHD-BD patients appear extremely urgent in order to better define possible therapeutic guidelines, as well as alternative approaches for this potentially invalidating condition.
Collapse
Affiliation(s)
- Federico Mucci
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,Fondazione BRF, Istituto per la Ricerca Scientifica in Psichiatria e Neuroscienze, Lucca, Italy
| | - Maria Teresa Avella
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Donatella Marazziti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,Fondazione BRF, Istituto per la Ricerca Scientifica in Psichiatria e Neuroscienze, Lucca, Italy
| |
Collapse
|
14
|
Schoretsanitis G, de Leon J, Eap CB, Kane JM, Paulzen M. Clinically Significant Drug-Drug Interactions with Agents for Attention-Deficit/Hyperactivity Disorder. CNS Drugs 2019; 33:1201-1222. [PMID: 31776871 DOI: 10.1007/s40263-019-00683-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This article provides an overview of the pharmacokinetic drug-drug interactions (DDIs) for agents prescribed for attention-deficit/hyperactivity disorder (ADHD). Polypharmacy in the treatment of patients with ADHD leads to high exposures to DDIs and possibly adverse safety outcomes. We performed a systematic search of DDI reports for ADHD agents in Embase and Medline. We also searched for agents in the pharmacological pipeline, which include (1) mazindol, molindone and viloxazine, which were previously prescribed for other indications; (2) centanafadine and AR-08, never before approved; and (3) two extracts (Polygala tenuifolia extract and the French maritime pine bark extracts). The identified literature included case reports, cross-sectional, cross-over and placebo-controlled studies of patient cohorts and healthy volunteers. The DDIs were classified as follows: ADHD agents acting as perpetrators, i.e., affecting the clearance of co-prescribed agents (victim drugs), or ADHD agents being the victim drugs, being affected by other agents. Ratios for changes in pharmacokinetic parameters before and after the DDI were used as a rough estimate of the extent of the DDI. Alcohol may increase plasma dextroamphetamine concentrations by presystemic effects. Until studies are done to orient clinicians regarding dosing changes, clinicians need to be aware of the potential for cytochrome P450 (CYP) 2D6 inhibitors to increase amphetamine levels, which is equivalent to increasing dosages. Atomoxetine is a wide therapeutic window drug. The CYP2D6 poor metabolizers who do not have CYP2D6 activity had better atomoxetine response, but also an increased risk of adverse effects. CYP2D6 inhibitors have been used to increase atomoxetine response in CYP2D6 extensive metabolizers. Guanfacine is mainly metabolized by CYP3A4, which can be induced and inhibited. The package insert recommends that in guanfacine-treated patients, after adding potent CYP3A4 inducers, the guanfacine dose should be doubled; after adding potent CYP3A4 inhibitors the guanfacine dose should be halved. Based on a phenobarbital case report and our experience with CYP3A4-metabolized antipsychotics, these correction factors may be too low. According to two case reports, carbamazepine is a clinically relevant inducer of methylphenidate (MPH). A case series study suggested that MPH may be associated with important elevations in imipramine concentrations. Due to the absence of or limitations in the data, no comments for clinicians can be provided on the pharmacokinetic DDIs for clonidine, centanafadine, mazindol, molindone, AR-08, P. tenuifolia extract and the French maritime pine bark extracts. According to currently available data, clinicians should not expect that ADHD drugs modify each other's serum concentrations. A summary table for clinicians provides our current recommendations on pharmacokinetic DDIs of ADHD agents based on our literature review and the package inserts; whenever it was possible, we provide information on serum concentrations and dose correction factors. There will be a need to periodically update these recommendations and these correction factors as new knowledge becomes available.
Collapse
Affiliation(s)
| | - Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, KY, USA
- Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain
- Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apostol Hospital, University of the Basque Country, Vitoria, Spain
| | - Chin B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Department of Psychiatry, Centre for Psychiatric Neuroscience, Lausanne University Hospital, Hospital of Cery, University of Lausanne, Prilly, Switzerland
- Institute of Pharmaceutical Sciences of Western, Switzerland University of Geneva, Geneva, Switzerland
| | - John M Kane
- The Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- The Hofstra Northwell School of Medicine, Hempstead, NY, USA
- The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Michael Paulzen
- Alexianer Hospital Aachen, Alexianergraben 33, 52062, Aachen, Germany.
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
- JARA-Translational Brain Medicine, Aachen, Germany.
| |
Collapse
|
15
|
Kim SH, Byeon JY, Kim YH, Lee CM, Lee YJ, Jang CG, Lee SY. Physiologically based pharmacokinetic modelling of atomoxetine with regard to CYP2D6 genotypes. Sci Rep 2018; 8:12405. [PMID: 30120390 PMCID: PMC6098032 DOI: 10.1038/s41598-018-30841-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/07/2018] [Indexed: 01/20/2023] Open
Abstract
Atomoxetine is a norepinephrine reuptake inhibitor indicated in the treatment of attention-deficit/hyperactivity disorder. It is primarily metabolized by CYP2D6 to its equipotent metabolite, 4-hydroxyatomoxetine, which promptly undergoes further glucuronidation to an inactive 4-HAT-O-glucuronide. Clinical trials have shown that decreased CYP2D6 activity leads to substantially elevated atomoxetine exposure and increase in adverse reactions. The aim of this study was to to develop a pharmacologically based pharmacokinetic (PBPK) model of atomoxetine in different CYP2D6 genotypes. A single 20 mg dose of atomoxetine was given to 19 healthy Korean individuals with CYP2D6*wt/*wt (*wt = *1 or *2) or CYP2D6*10/*10 genotype. Based on the results of this pharmacokinetic study, a PBPK model for CYP2D6*wt/*wt individuals was developed. This model was scaled to those with CYP2D6*10/*10 genotype, as well as CYP2D6 poor metabolisers. We validated this model by comparing the predicted pharmacokinetic parameters with diverse results from the literature. The presented PBPK model describes the pharmacokinetics after single and repeated oral atomoxetine doses with regard to CYP2D6 genotype and phenotype. This model could be utilized for identification of appropriate dosages of atomoxetine in patients with reduced CYP2D6 activity to minimize the adverse events, and to enable personalised medicine.
Collapse
Affiliation(s)
- Se-Hyung Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Ji-Young Byeon
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Young-Hoon Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Choong-Min Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Yun Jeong Lee
- College of Pharmacy, Dankook University, Cheonan, 31116, Republic of Korea
| | - Choon-Gon Jang
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Seok-Yong Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| |
Collapse
|
16
|
Huang W, Nakano M, Sager J, Ragueneau-Majlessi I, Isoherranen N. Physiologically Based Pharmacokinetic Model of the CYP2D6 Probe Atomoxetine: Extrapolation to Special Populations and Drug-Drug Interactions. Drug Metab Dispos 2017; 45:1156-1165. [PMID: 28860113 DOI: 10.1124/dmd.117.076455] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 08/28/2017] [Indexed: 01/18/2023] Open
Abstract
Physiologically based pharmacokinetic (PBPK) modeling of drug disposition and drug-drug interactions (DDIs) has become a key component of drug development. PBPK modeling has also been considered as an approach to predict drug disposition in special populations. However, whether models developed and validated in healthy populations can be extrapolated to special populations is not well established. The goal of this study was to determine whether a drug-specific PBPK model validated using healthy populations could be used to predict drug disposition in specific populations and in organ impairment patients. A full PBPK model of atomoxetine was developed using a training set of pharmacokinetic (PK) data from CYP2D6 genotyped individuals. The model was validated using drug-specific acceptance criteria and a test set of 14 healthy subject PK studies. Population PBPK models were then challenged by simulating the effects of ethnicity, DDIs, pediatrics, and renal and hepatic impairment on atomoxetine PK. Atomoxetine disposition was successfully predicted in 100% of healthy subject studies, 88% of studies in Asians, 79% of DDI studies, and 100% of pediatric studies. However, the atomoxetine area under the plasma concentration versus time curve (AUC) was overpredicted by 3- to 4-fold in end stage renal disease and hepatic impairment. The results show that validated PBPK models can be extrapolated to different ethnicities, DDIs, and pediatrics but not to renal and hepatic impairment patients, likely due to incomplete understanding of the physiologic changes in these conditions. These results show that systematic modeling efforts can be used to further refine population models to improve the predictive value in this area.
Collapse
Affiliation(s)
- Weize Huang
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
| | - Mariko Nakano
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
| | - Jennifer Sager
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
| | | | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
| |
Collapse
|
17
|
Todor I, Muntean D, Neag M, Bocsan C, Buzoianu A, Vlase L, Leucuta D, Gheldiu AM, Popa A, Briciu C. The Influence of CYP2D6 Phenotype on the Pharmacokinetic Profile of Atomoxetine in Caucasian Healthy Subjects. ACTA MEDICA MARISIENSIS 2017. [DOI: 10.1515/amma-2017-0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Abstract
Objective: To analyze a potential phenotypic variation within the studied group based on the pharmacokinetic profile of atomoxetine and its active metabolite, and to further investigate the impact of CYP2D6 phenotype on atomoxetine pharmacokinetics. Methods: The study was conducted as an open-label, non-randomized clinical trial which included 43 Caucasian healthy volunteers. Each subject received a single oral dose of atomoxetine 25 mg. Subsequently, atomoxetine and 4-hydroxyatomoxetine-O-glucuronide (glucuronidated active metabolite) plasma concentrations were determined and a noncompartmental method was used to calculate the pharmacokinetic parameters of both compounds. Further on, the CYP2D6 metabolic phenotype was assessed using the area under the curve (AUC) metabolic ratio (atomoxetine/ 4-hydroxyatomoxetine-O-glucuronide) and specific statistical tests (Lilliefors (Kolgomorov-Smirnov) and Anderson-Darling test). The phenotypic differences in atomoxetine disposition were identified based on the pharmacokinetic profile of the parent drug and its metabolite. Results: The statistical analysis revealed that the AUC metabolic ratio data set did not follow a normal distribution. As a result, two different phenotypes were identified, respectively the poor metabolizer (PM) group which included 3 individuals and the extensive metabolizer (EM) group which comprised the remaining 40 subjects. Also, it was demonstrated that the metabolic phenotype significantly influenced atomoxetine pharmacokinetics, as PMs presented a 4.5-fold higher exposure to the parent drug and a 3.2-fold lower exposure to its metabolite in comparison to EMs. Conclusions: The pharmacokinetic and statistical analysis emphasized the existence of 2 metabolic phenotypes: EMs and PMs. Furthermore, it was proved that the interphenotype variability had a marked influence on atomoxetine pharmacokinetic profile.
Collapse
Affiliation(s)
- Ioana Todor
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmaceutics, Cluj-Napoca , Romania
| | - Dana Muntean
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmaceutics, Cluj-Napoca , Romania
| | - Maria Neag
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Medicine, Department of Pharmacology, Toxicology and Clinical Pharmacology, Cluj-Napoca , Romania
| | - Corina Bocsan
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Medicine, Department of Pharmacology, Toxicology and Clinical Pharmacology, Cluj-Napoca , Romania
| | - Anca Buzoianu
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Medicine, Department of Pharmacology, Toxicology and Clinical Pharmacology, Cluj-Napoca , Romania
| | - Laurian Vlase
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmaceutics, Cluj-Napoca , Romania
| | - Daniel Leucuta
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Department of Medical Informatics and Biostatistics, Cluj-Napoca , Romania
| | - Ana-Maria Gheldiu
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmaceutics, Cluj-Napoca , Romania
| | - Adina Popa
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Clinical Pharmacy, Cluj-Napoca , Romania
| | - Corina Briciu
- University of Medicine and Pharmacy “Iuliu Hatieganu”, Faculty of Pharmacy, Department of Clinical Pharmacy, Cluj-Napoca , Romania
| |
Collapse
|
18
|
Yu G, Li GF, Markowitz JS. Atomoxetine: A Review of Its Pharmacokinetics and Pharmacogenomics Relative to Drug Disposition. J Child Adolesc Psychopharmacol 2016; 26:314-26. [PMID: 26859445 PMCID: PMC4876529 DOI: 10.1089/cap.2015.0137] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Atomoxetine is a selective norepinephrine (NE) reuptake inhibitor approved for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children (≥6 years of age), adolescents, and adults. Its metabolism and disposition are fairly complex, and primarily governed by cytochrome P450 (CYP) 2D6 (CYP2D6), whose protein expression varies substantially from person to person, and by race and ethnicity because of genetic polymorphism. These differences can be substantial, resulting in 8-10-fold differences in atomoxetine exposure between CYP2D6 poor metabolizers and extensive metabolizers. In this review, we have attempted to revisit and analyze all published clinical pharmacokinetic data on atomoxetine inclusive of public access documents from the new drug application submitted to the United States Food and Drug Administration (FDA). The present review focuses on atomoxetine metabolism, disposition, and genetic polymorphisms of CYP2D6 as they specifically relate to atomoxetine, and provides an in-depth discussion of the fundamental pharmacokinetics of the drug including its absorption, distribution, metabolism, and excretion in pediatric and adult populations. Further, a summary of relationships between genetic variants of CYP2D6 and to some degree, CYP2C19, are provided with respect to atomoxetine plasma concentrations, central nervous system (CNS) pharmacokinetics, and associated clinical implications for pharmacotherapy. Lastly, dosage adjustments based on pharmacokinetic principles are discussed.
Collapse
Affiliation(s)
- Guo Yu
- Laboratory of Pharmacogenomics and Pharmacokinetic Research, Subei People's Hospital, Yangzhou University, Yangzhou, Jiangsu, China
| | - Guo-Fu Li
- Center for Drug Clinical Research, Shanghai University of Chinese Medicine, Shanghai, China
| | - John S. Markowitz
- Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, Florida
- Center for Pharmacogenomics, University of Florida, Gainesville, Florida
| |
Collapse
|
19
|
Todor I, Popa A, Neag M, Muntean D, Bocsan C, Buzoianu A, Vlase L, Gheldiu AM, Chira R, Briciu C. The influence of paroxetine on the pharmacokinetics of atomoxetine and its main metabolite. ACTA ACUST UNITED AC 2016; 88:513-20. [PMID: 26733750 PMCID: PMC4689245 DOI: 10.15386/cjmed-488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 06/30/2015] [Accepted: 07/08/2015] [Indexed: 11/23/2022]
Abstract
Background and aims To evaluate the effects of paroxetine on the pharmacokinetics of atomoxetine and its main metabolite, 4-hydroxyatomoxetine-O-glucuronide, after coadministration of atomoxetine and paroxetine in healthy volunteers. Methods 22 healthy volunteers, extensive metabolizers, took part in this open-label, non-randomized, clinical trial. The study consisted of two periods: Reference, when a single oral dose of 25 mg atomoxetine was administrated to each subject and Test, when 25 mg atomoxetine and 20 mg paroxetine were coadministered. Between the two periods, the volunteers received an oral daily dose of 20–40 mg paroxetine, for 6 days. Atomoxetine and 4-hydroxyatomoxetine-O-glucuronide plasma concentrations were determined within the first 48 hours following drug administration. The pharmacokinetic parameters of both compounds were assessed using a non-compartmental method and the analysis of variance aimed at identifying any statistical significant differences between the pharmacokinetic parameters of atomoxetine and its main metabolite, corresponding to each study period. Results Paroxetine modified the pharmacokinetic parameters of atomoxetine. Cmax increased from 221.26±94.93 to 372.53±128.28 ng/mL, while AUC0-t and AUC0-∞ also increased from 1151.19±686.52 to 6452.37±3388.76 ng*h/mL, and from 1229.15±751.04 to 7111.74±4195.17 ng*h/mL respectively. The main metabolite pharmacokinetics was also influenced by paroxetine intake, namely Cmax, AUC0-t and AUC0-∞ decreased from 688.76±270.27 to 131.01±100.43 ng*h/mL, and from 4810.93±845.06 to 2606.04±923.88 and from 4928.55±853.25 to 3029.82 ±941.84 respectively. Conclusions Multiple-dose paroxetine intake significantly influenced atomoxetine and its active metabolite pharmacokinetics, causing a 5.8-fold increased exposure to atomoxetine and 1.6-fold reduced exposure to 4-hydroxyatomoxetine-O-glucuronide.
Collapse
Affiliation(s)
- Ioana Todor
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Adina Popa
- Department of Clinical Pharmacy, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Maria Neag
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Dana Muntean
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Corina Bocsan
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Anca Buzoianu
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Laurian Vlase
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Ana-Maria Gheldiu
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Ruxandra Chira
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Corina Briciu
- Department of Clinical Pharmacy, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| |
Collapse
|
20
|
Brown JT, Bishop JR. Atomoxetine pharmacogenetics: associations with pharmacokinetics, treatment response and tolerability. Pharmacogenomics 2015; 16:1513-20. [PMID: 26314574 DOI: 10.2217/pgs.15.93] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atomoxetine is indicated for the treatment of attention deficit hyperactivity disorder and is predominantly metabolized by the CYP2D6 enzyme. Differences in pharmacokinetic parameters as well as clinical treatment outcomes across CYP2D6 genotype groups have resulted in dosing recommendations within the product label, but clinical studies supporting the use of genotype guided dosing are currently lacking. Furthermore, pharmacokinetic and clinical studies have primarily focused on extensive as compared with poor metabolizers, with little information known about other metabolizer categories as well as genes involved in the pharmacodynamics of atomoxetine. This review describes the pharmacogenetic associations with atomoxetine pharmacokinetics, treatment response and tolerability with considerations for the clinical utility of this information.
Collapse
Affiliation(s)
- Jacob T Brown
- Department of Pharmacy Practice & Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN 55802, USA
| | - Jeffrey R Bishop
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
| |
Collapse
|
21
|
Markowitz JS, Brinda BJ. A pharmacokinetic evaluation of oral edivoxetine hydrochloride for the treatment of attention deficit-hyperactivity disorder. Expert Opin Drug Metab Toxicol 2014; 10:1289-99. [DOI: 10.1517/17425255.2014.939955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
22
|
Abstract
The aim of this study was to review current epidemiological data on the use of antidepressants in co-prescription with other psychotropic drugs in children and adolescents, as well as available efficacy and safety information. A Medline search from inception until February 2012 was performed to identify epidemiological and clinical studies, reviews and reports containing potentially relevant information on polypharmacy with antidepressants in young people. There has been an increase in polypharmacy in children and adolescents involving antidepressants in recent years. Antidepressants have become one of the drug classes most frequently prescribed in combination and are commonly co-prescribed with stimulants and antipsychotics. Most information regarding efficacy and safety of polypharmacy patterns was provided by case series and open-label studies. Efficacy studies gave some support for the use of a combination of antidepressants and antipsychotics in the management of refractory obsessive-compulsive disorder and some residual symptoms in major depressive disorder. Even less empirical support was found for a combination of stimulants and antidepressants in co-morbid attention deficit hyperactivity disorder and mood or anxiety disorders. Adverse events were similar to those found with individual medication groups, with severe adverse events mostly reported by individual case reports. The use of polypharmacy with antidepressants has become a regular practice in clinical settings. Although there is still little efficacy and safety information, preliminary evidence points to the potential clinical usefulness of some polypharmacy patterns. Further research on patients with co-morbidities or more severe conditions is needed, in order to improve knowledge of this issue.
Collapse
|
23
|
Sager JE, Lutz JD, Foti RS, Davis C, Kunze KL, Isoherranen N. Fluoxetine- and norfluoxetine-mediated complex drug-drug interactions: in vitro to in vivo correlation of effects on CYP2D6, CYP2C19, and CYP3A4. Clin Pharmacol Ther 2014; 95:653-62. [PMID: 24569517 PMCID: PMC4029899 DOI: 10.1038/clpt.2014.50] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 02/14/2014] [Indexed: 01/14/2023]
Abstract
Fluoxetine and its circulating metabolite norfluoxetine comprise a complex multiple-inhibitor system that causes reversible or time-dependent inhibition of the cytochrome P450 (CYP) family members CYP2D6, CYP3A4, and CYP2C19 in vitro. Although significant inhibition of all three enzymes in vivo was predicted, the areas under the concentration-time curve (AUCs) for midazolam and lovastatin were unaffected by 2-week dosing of fluoxetine, whereas the AUCs of dextromethorphan and omeprazole were increased by 27- and 7.1-fold, respectively. This observed discrepancy between in vitro risk assessment and in vivo drug-drug interaction (DDI) profile was rationalized by time-varying dynamic pharmacokinetic models that incorporated circulating concentrations of fluoxetine and norfluoxetine enantiomers, mutual inhibitor-inhibitor interactions, and CYP3A4 induction. The dynamic models predicted all DDIs with less than twofold error. This study demonstrates that complex DDIs that involve multiple mechanisms, pathways, and inhibitors with their metabolites can be predicted and rationalized via characterization of all the inhibitory species in vitro.
Collapse
Affiliation(s)
- J E Sager
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - J D Lutz
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - R S Foti
- Department of Pharmacokinetics and Drug Metabolism, Amgen, Seattle, Washington, USA
| | - C Davis
- Division of Nephrology, Department of Medicine, School of Medicine, University of Washington, Seattle, Washington, USA
| | - K L Kunze
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - N Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA
| |
Collapse
|
24
|
Choi CI, Jang CG, Bae JW, Lee SY. Validation of an analytical LC-MS/MS method in human plasma for the pharmacokinetic study of atomoxetine. JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1134/s1061934813110051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
25
|
Yeo KR, Jamei M, Rostami-Hodjegan A. Predicting drug-drug interactions: application of physiologically based pharmacokinetic models under a systems biology approach. Expert Rev Clin Pharmacol 2013; 6:143-57. [PMID: 23473592 DOI: 10.1586/ecp.13.4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The development of in vitro-in vivo extrapolation (IVIVE), a 'bottom-up' approach, to predict pharmacokinetic parameters and drug-drug interactions (DDIs) has accelerated mainly due to an increase in the understanding of the multiple mechanisms involved in these interactions and the availability of appropriate in vitro systems that act as surrogates for delineating various elements of the interactions relevant to absorption, distribution, metabolism and elimination. Recent advances in the knowledge of the population variables required for IVIVE (demographic, anatomical, genetic and physiological parameters) have also contributed to the appreciation of the sources of variability and wider use of this approach for different scenarios within the pharmaceutical industry. Initially, the authors present an overview of the integration of IVIVE into 'static' and 'dynamic' models for the quantitative prediction of DDIs. The main purpose of this review is to discuss the application of IVIVE in conjunction with physiologically based pharmacokinetic modeling under a systems biology approach to characterize the potential DDIs in individual patients, including those who cannot be investigated in formal clinical trials for ethical reasons. In addition, we address the issues related to the prediction of complex DDIs involving the inhibition of cytochrome P- and transporter-mediated activities through multiple drugs.
Collapse
Affiliation(s)
- Karen Rowland Yeo
- Simcyp Limited, Blades Enterprise Centre, John Street, Sheffield S2 4SU, UK.
| | | | | |
Collapse
|
26
|
Stepan AF, Mascitti V, Beaumont K, Kalgutkar AS. Metabolism-guided drug design. MEDCHEMCOMM 2013. [DOI: 10.1039/c2md20317k] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
27
|
Isoherranen N, Lutz JD, Chung SP, Hachad H, Levy RH, Ragueneau-Majlessi I. Importance of multi-p450 inhibition in drug-drug interactions: evaluation of incidence, inhibition magnitude, and prediction from in vitro data. Chem Res Toxicol 2012; 25:2285-300. [PMID: 22823924 PMCID: PMC3502654 DOI: 10.1021/tx300192g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Drugs that are mainly cleared by a single enzyme are considered more sensitive to drug-drug interactions (DDIs) than drugs cleared by multiple pathways. However, whether this is true when a drug cleared by multiple pathways is coadministered with an inhibitor of multiple P450 enzymes (multi-P450 inhibition) is not known. Mathematically, simultaneous equipotent inhibition of two elimination pathways that each contribute half of the drug clearance is equal to equipotent inhibition of a single pathway that clears the drug. However, simultaneous strong or moderate inhibition of two pathways by a single inhibitor is perceived as an unlikely scenario. The aim of this study was (i) to identify P450 inhibitors currently in clinical use that can inhibit more than one clearance pathway of an object drug in vivo and (ii) to evaluate the magnitude and predictability of DDIs caused by these multi-P450 inhibitors. Multi-P450 inhibitors were identified using the Metabolism and Transport Drug Interaction Database. A total of 38 multi-P450 inhibitors, defined as inhibitors that increased the AUC or decreased the clearance of probes of two or more P450s, were identified. Seventeen (45%) multi-P450 inhibitors were strong inhibitors of at least one P450, and an additional 12 (32%) were moderate inhibitors of one or more P450s. Only one inhibitor (fluvoxamine) was a strong inhibitor of more than one enzyme. Fifteen of the multi-P450 inhibitors also inhibit drug transporters in vivo, but such data are lacking on many of the inhibitors. Inhibition of multiple P450 enzymes by a single inhibitor resulted in significant (>2-fold) clinical DDIs with drugs that are cleared by multiple pathways such as imipramine and diazepam, while strong P450 inhibitors resulted in only weak DDIs with these object drugs. The magnitude of the DDIs between multi-P450 inhibitors and diazepam, imipramine, and omeprazole could be predicted using in vitro data with similar accuracy as probe substrate studies with the same inhibitors. The results of this study suggest that inhibition of multiple clearance pathways in vivo is clinically relevant, and the risk of DDIs with object drugs may be best evaluated in studies using multi-P450 inhibitors.
Collapse
Affiliation(s)
- Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA.
| | | | | | | | | | | |
Collapse
|
28
|
Kielbasa W, Quinlan T, Jin L, Xu W, Lachno DR, Dean RA, Allen AJ. Pharmacokinetics and pharmacodynamics of edivoxetine (LY2216684), a norepinephrine reuptake inhibitor, in pediatric patients with attention-deficit/hyperactivity disorder. J Child Adolesc Psychopharmacol 2012; 22:269-76. [PMID: 22849510 DOI: 10.1089/cap.2011.0151] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Edivoxetine (LY2216684) is a selective and potent norepinephrine reuptake inhibitor (NERI). The pharmacokinetics (PK) and pharmacodynamics (PD) of edivoxetine were assessed in children and adolescent patients with attention-deficit/hyperactivity disorder (ADHD) following single and once-daily oral doses of edivoxetine. METHODS During a phase 1 open-label safety, tolerability, and PK study, pediatric patients were administered edivoxetine at target doses of 0.05, 0.1, 0.2 and 0.3 mg/kg, and blood samples were collected to determine plasma concentrations of edivoxetine for PK assessments and plasma 3,4-dihydroxyphenylglycol (DHPG) concentrations for PD assessments. Edivoxetine plasma concentrations were measured using liquid chromatography with tandem mass spectrometric detection, and DHPG was measured using liquid chromatography with electrochemical detection. RESULTS Edivoxetine PK was comparable between children and adolescents. The time to maximum concentration (t(max)) of edivoxetine was ∼2 hours, which was followed by a mono-exponential decline in plasma concentrations with a terminal elimination half-life (t(1/2)) of ∼6 hours. Dose-dependent increases in area under the edivoxetine plasma concentration versus time curve from zero to infinity (AUC(0-∞)) and maximum plasma concentration (C(max)) were observed, and there was no discernable difference in the apparent clearance (CL/F) or the apparent volume of distribution at steady state (V(ss)/F) across the dose range. In adolescents, edivoxetine caused a maximum decrease in plasma DHPG concentrations from baseline of ∼28%, most notably within 8 hours of edivoxetine administration. CONCLUSION This initial study in pediatric patients with ADHD provides new information on the PK profile of edivoxetine, and exposures that decrease plasma DHPG consistent with the mechanism of action of a NERI. The PK and PD data inform edivoxetine pharmacology and can be used to develop comprehensive population PK and/or PK-PD models to guide dosing strategies.
Collapse
Affiliation(s)
- William Kielbasa
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
| | | | | | | | | | | | | |
Collapse
|
29
|
Fujioka Y, Kunze KL, Isoherranen N. Risk assessment of mechanism-based inactivation in drug-drug interactions. Drug Metab Dispos 2012; 40:1653-7. [PMID: 22685217 DOI: 10.1124/dmd.112.046649] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Drug-drug interactions (DDIs) that occur via mechanism-based inactivation of cytochrome P450 are of serious concern. Although several predictive models have been published, early risk assessment of MBIs is still challenging. For reversible inhibitors, the DDI risk categorization using [I]/K(i) ([I], the inhibitor concentration; K(i), the inhibition constant) is widely used in drug discovery and development. Although a simple and reliable methodology such as [I]/K(i) categorization for reversible inhibitors would be useful for mechanism-based inhibitors (MBIs), comprehensive analysis of an analogous measure reflecting in vitro potency for inactivation has not been reported. The aim of this study was to evaluate whether the term λ/k(deg) (λ, first-order inactivation rate at a given MBI concentration; k(deg), enzyme degradation rate constant) would be useful in the prediction of the in vivo DDI risk of MBIs. Twenty-one MBIs with both in vivo area under the curve (AUC) change of marker substrates and in vitro inactivation parameters were identified in the literature and analyzed. The results of this analysis show that in vivo DDIs with >2-fold change of object drug AUC can be identified with the cutoff value of λ/k(deg) = 1, where unbound steady-state C(max) is used for inhibitor concentration. However, the use of total C(max) led to great overprediction of DDI risk. The risk assessment using λ/k(deg) coupled with unbound C(max) can be useful for the DDI risk evaluation of MBIs in drug discovery and development.
Collapse
Affiliation(s)
- Yasushi Fujioka
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
| | | | | |
Collapse
|
30
|
Orr STM, Ripp SL, Ballard TE, Henderson JL, Scott DO, Obach RS, Sun H, Kalgutkar AS. Mechanism-based inactivation (MBI) of cytochrome P450 enzymes: structure-activity relationships and discovery strategies to mitigate drug-drug interaction risks. J Med Chem 2012; 55:4896-933. [PMID: 22409598 DOI: 10.1021/jm300065h] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Suvi T M Orr
- Worldwide Medicinal Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Chiba K, Kato M, Ito T, Suwa T, Sugiyama Y. Inter-individual Variability of In Vivo CYP2D6 Activity in Different Genotypes. Drug Metab Pharmacokinet 2012; 27:405-13. [DOI: 10.2133/dmpk.dmpk-11-rg-078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
32
|
Chan A, Ng TRD, Yap KYL. Clinically–relevant anticancer-antidepressant drug interactions. Expert Opin Drug Metab Toxicol 2011; 8:173-99. [DOI: 10.1517/17425255.2012.645804] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
33
|
Inhibition of CYP3A4 and CYP2C9 by podophyllotoxin: Implication for clinical drug–drug interactions. J Biosci 2011; 36:879-85. [DOI: 10.1007/s12038-011-9143-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
34
|
Yap KYL, Tay WL, Chui WK, Chan A. Clinically relevant drug interactions between anticancer drugs and psychotropic agents. Eur J Cancer Care (Engl) 2011; 20:6-32. [PMID: 20030690 DOI: 10.1111/j.1365-2354.2009.01113.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Drug interactions are commonly seen in the treatment of cancer patients. Psychotropics are often indicated for these patients since they may also suffer from pre-existing psychological disorders or experience insomnia and anxiety associated with cancer therapy. Thus, the risk of anticancer drug (ACD)-psychotropic drug-drug interactions (DDIs) is high. Drug interactions were compiled from the British National Formulary (53rd edn), Lexi-Comp's Drug Information Handbook (15th edn), Micromedex (v5.1), Hansten & Horn's Drug Interactions (2000) and Drug Interaction Facts (2008 edn). Product information of the individual drugs, as well as documented literature on ACD-psychotropic interactions from PubMed and other databases was also incorporated. This paper identifies clinically important ACD-psychotropic DDIs that are frequently observed. Pharmacokinetic DDIs were observed for tyrosine kinase inhibitors, corticosteroids and antimicrotubule agents due to their inhibitory or inductive effects on cytochrome P450 isoenzymes. Pharmacodynamic DDIs were identified for thalidomide with central nervous system depressants, procarbazine with antidepressants, myelosuppressive ACDs with clozapine and anthracyclines with QT-prolonging psychotropics. Clinicians should be vigilant when psychotropics are prescribed concurrently with ACDs. Close monitoring of plasma drug levels should be carried out to avoid toxicity in the patient, as well as to ensure adequate chemotherapeutic and psychotropic coverage.
Collapse
Affiliation(s)
- K Y-L Yap
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore
| | | | | | | |
Collapse
|
35
|
Kobayashi T, Washiyama K, Ikeda K. Inhibition of G-protein-activated inwardly rectifying K+ channels by the selective norepinephrine reuptake inhibitors atomoxetine and reboxetine. Neuropsychopharmacology 2010; 35:1560-9. [PMID: 20393461 PMCID: PMC3055469 DOI: 10.1038/npp.2010.27] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Atomoxetine and reboxetine are commonly used as selective norepinephrine reuptake inhibitors (NRIs) for the treatment of attention-deficit/hyperactivity disorder and depression, respectively. Furthermore, recent studies have suggested that NRIs may be useful for the treatment of several other psychiatric disorders. However, the molecular mechanisms underlying the various effects of NRIs have not yet been sufficiently clarified. G-protein-activated inwardly rectifying K(+) (GIRK or Kir3) channels have an important function in regulating neuronal excitability and heart rate, and GIRK channel modulation has been suggested to be a potential treatment for several neuropsychiatric disorders and cardiac arrhythmias. In this study, we investigated the effects of atomoxetine and reboxetine on GIRK channels using the Xenopus oocyte expression assay. In oocytes injected with mRNA for GIRK1/GIRK2, GIRK2, or GIRK1/GIRK4 subunits, extracellular application of atomoxetine or reboxetine reversibly reduced GIRK currents. The inhibitory effects were concentration-dependent, but voltage-independent, and time-independent during each voltage pulse. However, Kir1.1 and Kir2.1 channels were insensitive to atomoxetine and reboxetine. Atomoxetine and reboxetine also inhibited GIRK currents induced by activation of cloned A(1) adenosine receptors or by intracellularly applied GTPgammaS, a nonhydrolyzable GTP analogue. Furthermore, the GIRK currents induced by ethanol were concentration-dependently inhibited by extracellularly applied atomoxetine but not by intracellularly applied atomoxetine. The present results suggest that atomoxetine and reboxetine inhibit brain- and cardiac-type GIRK channels, revealing a novel characteristic of clinically used NRIs. GIRK channel inhibition may contribute to some of the therapeutic effects of NRIs and adverse side effects related to nervous system and heart function.
Collapse
Affiliation(s)
- Toru Kobayashi
- Department of Molecular Neuropathology, Brain Research Institute, Niigata University, Chuo-ku, Niigata, Japan.
| | - Kazuo Washiyama
- Department of Molecular Neuropathology, Brain Research Institute, Niigata University, Chuo-ku, Niigata, Niigata, Japan
| | - Kazutaka Ikeda
- Division of Psychobiology, Tokyo Institute of Psychiatry, Setagaya-ku, Tokyo, Japan
| |
Collapse
|
36
|
Dezentjé VO, van Blijderveen NJC, Gelderblom H, Putter H, van Herk-Sukel MPP, Casparie MK, Egberts ACG, Nortier JWR, Guchelaar HJ. Effect of concomitant CYP2D6 inhibitor use and tamoxifen adherence on breast cancer recurrence in early-stage breast cancer. J Clin Oncol 2010; 28:2423-9. [PMID: 20385997 DOI: 10.1200/jco.2009.25.0894] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The use of cytochrome P450 2D6-inhibiting drugs (CYP2D6 inhibitors) during tamoxifen treatment leads to a decrease in plasma concentration of endoxifen, the major active tamoxifen metabolite. Concomitant use of CYP2D6 inhibitors, such as selective serotonin reuptake inhibitors, as well as low tamoxifen adherence may negatively impact tamoxifen efficacy in patients with breast cancer. The objectives of this study were to relate concomitant CYP2D6 inhibitor use and tamoxifen adherence to breast cancer event-free time (EFT). PATIENTS AND METHODS Data were from PHARMO and included a community pharmacy dispensing database; PALGA, a nationwide pathology database; and the Dutch Medical Register in the Netherlands. Patients with breast cancer treated with adjuvant tamoxifen between 1994 and 2006 were included. A Cox proportional hazards model with a time-dependent definition for concomitant CYP2D6 inhibitor exposure was used. Adherence calculated over the first year after tamoxifen initiation was related to breast cancer events in the following period. RESULTS In total, 1,962 patients with breast cancer using tamoxifen were included, among whom 150 (7.6%) frequently used a CYP2D6 inhibitor during tamoxifen treatment. No association between concomitant CYP2D6 inhibitor use and breast cancer recurrence was observed (adjusted hazard ratio [HR], 0.87; 95% CI, 0.42 to 1.79; P = .69). Poor tamoxifen adherence was associated with lower EFT (adjusted HR, 0.987; 95% CI, 0.975 to 0.999; P = .029). CONCLUSION This observational study did not show an association between concomitant CYP2D6 inhibitor use and breast cancer recurrence among patients treated with adjuvant tamoxifen despite the strong biologic rationale. This study shows, to the best of our knowledge for the first time, that poor tamoxifen adherence is associated with an increased risk of breast cancer events.
Collapse
Affiliation(s)
- Vincent O Dezentjé
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Garnock-Jones KP, Keating GM. Spotlight on atomoxetine in attention-deficit hyperactivity disorder in children and adolescents. CNS Drugs 2010; 24:85-8. [PMID: 20030421 DOI: 10.2165/11203670-000000000-00000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Atomoxetine (Strattera) is a selective noradrenaline (norepinephrine) reuptake inhibitor that is not classified as a stimulant, and is indicated for use in patients with attention-deficit hyperactivity disorder (ADHD). Atomoxetine is effective and generally well tolerated. It is significantly more effective than placebo and standard current therapy and does not differ significantly from, or is noninferior to, immediate-release methylphenidate; however, it is significantly less effective than the extended-release methylphenidate formulation OROS methylphenidate (hereafter referred to as osmotically released methylphenidate) and extended-release mixed amfetamine salts. Atomoxetine can be administered either as a single daily dose or split into two evenly divided doses, has a negligible risk of abuse or misuse and is not a controlled substance in the US. Atomoxetine is particularly useful for patients at risk of substance abuse, as well as those who have co-morbid anxiety or tics, or who do not wish to take a controlled substance. Thus, atomoxetine is a useful option in the treatment of ADHD in children and adolescents.
Collapse
|
38
|
Janknegt R, Faber A, Rodrigues Pereira R, Kalverdijk LJ. InforMatrix for attention deficit hyperactivity disorder. Expert Opin Pharmacother 2009; 10:755-72. [PMID: 19351226 DOI: 10.1517/14656560902765769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The purpose of this review is to facilitate discussion on drug selection for the treatment of ADHD by using only clinically relevant selection criteria and providing an up-to-date overview. The InforMatrix method was used to select drugs to treat attention deficit hyperactivity disorder (ADHD). The following selection criteria were applied: clinical efficacy, safety, tolerability, ease of use, applicability, and cost. The drugs approved for ADHD in the Netherlands were included in the analysis, namely: atomoxetine, immediate-release methylphenidate, and various formulations of slow-release methylphenidate (Concerta, Equasym and Medikinet). Most studies are of limited quality, duration, and size. In one study, Concerta was more effective than atomoxetine. Although no relevant differences were seen in other comparative studies, the clinical experience with atomoxetine is still limited and unexpected toxicity cannot be excluded; few studies have been published with Equasym and Medikinet. No major differences were seen in general tolerability between the drugs. The ease of use of immediate-release methylphenidate is less than for the other drugs. The acquisition cost of immediate-release methylphenidate is considerably lower than that of the slow-release formulations. Atomoxetine is the most expensive drug. The InforMatrix program is available in an interactive format. It enables the user to judge both the importance of the selection criteria and the properties of each therapeutic option per criterion on the basis of his or her own personal expertise and/or the present document.
Collapse
Affiliation(s)
- Robert Janknegt
- Hospital Pharmacist, Clinical Pharmacologist Maasland Ziekenhuis, Postbus, Sittard, The Netherlands.
| | | | | | | |
Collapse
|
39
|
Garnock-Jones KP, Keating GM. Atomoxetine: a review of its use in attention-deficit hyperactivity disorder in children and adolescents. Paediatr Drugs 2009; 11:203-26. [PMID: 19445548 DOI: 10.2165/00148581-200911030-00005] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Atomoxetine (Strattera(R)) is a selective norepinephrine (noradrenaline) reuptake inhibitor that is not classified as a stimulant, and is indicated for use in patients with attention-deficit hyperactivity disorder (ADHD). Atomoxetine is effective and generally well tolerated. It is significantly more effective than placebo and standard current therapy and does not differ significantly from or is noninferior to immediate-release methylphenidate; however, it is significantly less effective than the extended-release methylphenidate formulation OROS(R) methylphenidate (hereafter referred to as osmotically released methylphenidate) and extended-release mixed amfetamine salts. Atomoxetine can be administered either as a single daily dose or split into two evenly divided doses, has a negligible risk of abuse or misuse, and is not a controlled substance in the US. Atomoxetine is particularly useful for patients at risk of substance abuse, as well as those who have co-morbid anxiety or tics, or who do not wish to take a controlled substance. Thus, atomoxetine is a useful option in the treatment of ADHD in children and adolescents. The mechanism of action of atomoxetine is unclear, but is thought to be related to its selective inhibition of presynaptic norepinephrine reuptake in the prefrontal cortex. Atomoxetine has a high affinity and selectivity for norepinephrine transporters, but little or no affinity for various neurotransmitter receptors. Atomoxetine has a demonstrated ability to selectively inhibit norepinephrine uptake in humans and animals, and studies have shown that it preferentially binds to areas of known high distribution of noradrenergic neurons, such as the fronto-cortical subsystem. Atomoxetine was generally associated with statistically, but not clinically, significant increases in both heart rate and blood pressure in pediatric patients with ADHD. While there was an initial loss in expected height and weight among atomoxetine recipients, this eventually returned to normal in the longer term. Data suggest that atomoxetine is unlikely to have any abuse potential. Atomoxetine appeared less likely than methylphenidate to exacerbate disordered sleep in pediatric patients with ADHD. Atomoxetine is rapidly absorbed, and demonstrates dose-proportional increases in plasma exposure. It undergoes extensive biotransformation, which is affected by poor metabolism by cytochrome P450 (CYP) 2D6 in a small percentage of the population; these patients have greater exposure to and slower elimination of atomoxetine than extensive metabolizers. Patients with hepatic insufficiency show an increase in atomoxetine exposure. CYP2D6 inhibitors, such as paroxetine, are associated with changes in atomoxetine pharmacokinetics similar to those observed among poor CYP2D6 metabolizers. Once- or twice-daily atomoxetine was effective in the short-term treatment of ADHD in children and adolescents, as observed in several well designed placebo-controlled trials. Atomoxetine also demonstrated efficacy in the longer term treatment of these patients. A single morning dose was shown to be effective into the evening, and discontinuation of atomoxetine was not associated with symptom rebound. Atomoxetine efficacy did not appear to differ between children and adolescents. Stimulant-naive patients also responded well to atomoxetine treatment. Atomoxetine did not differ significantly from or was noninferior to immediate-release methylphenidate in children and adolescents with ADHD with regard to efficacy, and was significantly more effective than standard current therapy (any combination of medicines [excluding atomoxetine] and/or behavioral counseling, or no treatment). However, atomoxetine was significantly less effective than osmotically released methylphenidate and extended-release mixed amfetamine salts. The efficacy of atomoxetine did not appear to be affected by the presence of co-morbid disorders, and symptoms of the co-morbid disorders were not affected or were improved by atomoxetine administration. Health-related quality of life (HR-QOL) appeared to be positively affected by atomoxetine in both short- and long-term studies; atomoxetine also improved HR-QOL to a greater extent than standard current therapy. Atomoxetine was generally well tolerated in children and adolescents with ADHD. Common adverse events included headache, abdominal pain, decreased appetite, vomiting, somnolence, and nausea. The majority of adverse events were mild or moderate; there was a very low incidence of serious adverse events. Few patients discontinued atomoxetine treatment because of adverse events. Atomoxetine discontinuation appeared to be well tolerated, with a low incidence of discontinuation-emergent adverse events. Atomoxetine appeared better tolerated among extensive CYP2D6 metabolizers than among poor metabolizers. Slight differences were evident in the adverse event profiles of atomoxetine and stimulants, both immediate- and extended-release. Somnolence appeared more common among atomoxetine recipients and insomnia appeared more common among stimulant recipients. A black-box warning for suicidal ideation has been published in the US prescribing information, based on findings from a meta-analysis showing that atomoxetine is associated with a significantly higher incidence of suicidal ideation than placebo. Rarely, atomoxetine may also be associated with serious liver injury; postmarketing data show that three patients have had liver-related adverse events deemed probably related to atomoxetine treatment. Treatment algorithms involving the initial use of atomoxetine appear cost effective versus algorithms involving initial methylphenidate (immediate- or extended-release), dexamfetamine, tricyclic antidepressants, or no treatment in stimulant-naive, -failed, and -contraindicated children and adolescents with ADHD. The incremental cost per quality-adjusted life-year is below commonly accepted cost-effectiveness thresholds, as shown in several Markov model analyses conducted from the perspective of various European countries, with a time horizon of 1 year.
Collapse
Affiliation(s)
- Karly P Garnock-Jones
- Wolters Kluwer Health mid R: Adis, Auckland, New Zealand, an editorial office of Wolters Kluwer Health, Philadelphia, Pennsylvania, USA.
| | | |
Collapse
|
40
|
Vaughan B, Fegert J, Kratochvil CJ. Update on atomoxetine in the treatment of attention-deficit/hyperactivity disorder. Expert Opin Pharmacother 2009; 10:669-76. [DOI: 10.1517/14656560902762873] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
41
|
Clinically relevant pharmacokinetic drug interactions with second-generation antidepressants: an update. Clin Ther 2008; 30:1206-27. [PMID: 18691982 DOI: 10.1016/s0149-2918(08)80047-1] [Citation(s) in RCA: 217] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND The second-generation antidepressants include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and other compounds with different mechanisms of action. All second-generation antidepressants are metabolized in the liver by the cytochrome P450 (CYP) enzyme system. Concomitant intake of inhibitors or inducers of the CYP isozymes involved in the biotransformation of specific antidepressants may alter plasma concentrations of these agents, although this effect is unlikely to be associated with clinically relevant interactions. Rather, concern about drug interactions with second-generation antidepressants is based on their in vitro potential to inhibit > or = 1 CYP isozyme. OBJECTIVE The goal of this article was to review the current literature on clinically relevant pharmacokinetic drug interactions with second-generation antidepressants. METHODS A search of MEDLINE and EMBASE was conducted for original research and review articles published in English between January 1985 and February 2008. Among the search terms were drug interactions, second-generation antidepressants, newer antidepressants, SSRIs, SNRIs, fluoxetine, paroxetine, fluvoxamine, sertraline, citalopram, escitalopram, venlafaxine, duloxetine, mirtazapine, reboxetine, bupropion, nefazodone, pharmacokinetics, drug metabolism, and cytochrome P450. Only articles published in peer-reviewed journals were included, and meeting abstracts were excluded. The reference lists of relevant articles were hand-searched for additional publications. RESULTS Second-generation antidepressants differ in their potential for pharmacokinetic drug interactions. Fluoxetine and paroxetine are potent inhibitors of CYP2D6, fluvoxamine markedly inhibits CYP1A2 and CYP2C19, and nefazodone is a substantial inhibitor of CYP3A4. Therefore, clinically relevant interactions may be expected when these antidepressants are coadministered with substrates of the pertinent isozymes, particularly those with a narrow therapeutic index. Duloxetine and bupropion are moderate inhibitors of CYP2D6, and sertraline may cause significant inhibition of this isoform, but only at high doses. Citalopram, escitalopram, venlafaxine, mirtazapine, and reboxetine are weak or negligible inhibitors of CYP isozymes in vitro and are less likely than other second-generation antidepressants to interact with co-administered medications. CONCLUSIONS Second-generation antidepressants are not equivalent in their potential for pharmacokinetic drug interactions. Although interactions may be predictable in specific circumstances, use of an antidepressant with a more favorable drug-interaction profile may be justified.
Collapse
|
42
|
Bond GR, Garro AC, Gilbert DL. Dyskinesias associated with atomoxetine in combination with other psychoactive drugs. Clin Toxicol (Phila) 2008; 45:182-5. [PMID: 17364639 DOI: 10.1080/15563650600981178] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Toxicity experience with atomoxetine, a selective norepinephrine reuptake inhibitor approved for Attention Deficit Hyperactivity Disorder (ADHD), is limited. We report two cases of neurologic complications requiring hospitalization in patients when atomoxetine was added to other psychoactive drugs. A 9-year-old taking clonidine and dextroamphetamine developed psychosis, abnormal involuntary movements, and insomnia. An 18-year-old also initiating venlafaxine developed facial tics, tremors, and speech disturbance. Acute symptoms did not respond to diphenhydramine in either case, but resolved after atomoxetine and other medications were discontinued. Possible explanations include atypical atomoxetine effect, excess atomoxetine or metabolites due to poor metabolizer status (CYP 2D6 polymorphism/deficiency), a drug-drug interaction leading to elevated drug levels or to excess synaptic norepinephrine or dopamine. Serotonin syndrome is a possibility in the second case, but not the first. Clinicians should be aware of emergent dyskinesias when combining atomoxetine with dopaminergic, noradrenergic, or serotonergic medications.
Collapse
Affiliation(s)
- G Randall Bond
- Drug and Poison Information Center, and Division of Emergency Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, Ohio. USA
| | | | | |
Collapse
|
43
|
Prasad S, Steer C. Switching from neurostimulant therapy to atomoxetine in children and adolescents with attention-deficit hyperactivity disorder : clinical approaches and review of current available evidence. Paediatr Drugs 2008; 10:39-47. [PMID: 18162007 DOI: 10.2165/00148581-200810010-00005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
This review provides practical information on and clinical reasons for switching children and young people with attention-deficit hyperactivity disorder (ADHD) from neurostimulants to atomoxetine, detailing currently available evidence, and switching options. The issue is of particular relevance following recent guidance from the National Institute for Health and Clinical Excellence and European ADHD guidelines endorsing the use of atomoxetine, along with the stimulants methylphenidate and dexamphetamine, in the management of ADHD in children and adolescents in the UK. The selective norepinephrine (noradrenaline) reuptake inhibitor, atomoxetine, is a non-stimulant drug licensed for the treatment of ADHD in children and adolescents, and in adults who have shown a response in childhood. Following the once-daily morning dose, its therapeutic effects extend through the waking hours, into late evening, and in some patients, through to early the next morning. Atomoxetine may be considered for patients who are unresponsive or incompletely responsive to stimulant treatment, have co-morbid conditions (e.g. tics, anxiety, depression), and have sleep disturbances or eating problems, for patients in whom stimulants are poorly tolerated, and for situations where there is potential for drug abuse or diversion. Atomoxetine has been shown to be effective in relapse prevention and there is suggestion that atomoxetine may have a positive effect on global functioning; specifically health-related quality of life, self-esteem, and social and family functioning. According to one study, approximately 50% of non-responders to methylphenidate will respond to atomoxetine therapy and approximately 75% of responders to methylphenidate will also respond to atomoxetine. Atomoxetine may be initiated by a schedule of dose increases and cross-tapering with methylphenidate. A slow titration schedule with divided doses minimizes the impact of adverse events within the first several weeks of treatment. Atomoxetine may be co-administered with methylphenidate during the switching period without undue concern for adverse events, such as cardiovascular effects (although monitoring of blood pressure and heart rate is necessary). Atomoxetine may be discontinued abruptly and patients may miss the occasional dose without rebound effects or discontinuation syndrome. A trial period of at least 6-8 weeks, perhaps longer, is recommended before evaluation of the overall tolerability and efficacy of atomoxetine. We conclude that patients with ADHD can be switched from neurostimulants, specifically methylphenidate, to atomoxetine, and may benefit from symptom improvement.
Collapse
Affiliation(s)
- Suyash Prasad
- Department of Paediatrics, Cromwell Hospital, London, UK.
| | | |
Collapse
|
44
|
Kolar D, Keller A, Golfinopoulos M, Cumyn L, Syer C, Hechtman L. Treatment of adults with attention-deficit/hyperactivity disorder. Neuropsychiatr Dis Treat 2008; 4:389-403. [PMID: 18728745 PMCID: PMC2518387 DOI: 10.2147/ndt.s6985] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
This review focuses on the treatment of attention deficit hyperactivity disorder (ADHD) in adults. It briefly addresses prevalence, diagnostic and differential diagnostic issues specific to adults. Stimulant medication, non-stimulant medication, and psychosocial treatments are thoroughly reviewed. For each class of medication possible mechanism of action, efficacy and side effects are summarized. Special attention is given to the pharmacological treatment for patients with adult ADHD and various comorbidities. In summary, stimulant medications are most effective and combined medication and psychosocial treatment is the most beneficial treatment option for most adult patients with ADHD.
Collapse
Affiliation(s)
- Dusan Kolar
- Department of Psychiatry, Montreal Children's Hospital, McGill University Montreal, Canada
| | | | | | | | | | | |
Collapse
|
45
|
|
46
|
Kolar D, Keller A, Golfinopoulos M, Cumyn L, Syer C, Hechtman L. Treatment of adults with attention-deficit/hyperactivity disorder. Neuropsychiatr Dis Treat 2008; 4:107-21. [PMID: 18728812 PMCID: PMC2515906 DOI: 10.2147/ndt.s1747] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This review focuses on the treatment of attention deficit hyperactivity disorder (ADHD) in adults. It briefly addresses prevalence, diagnostic and differential diagnostic issues specific to adults. Stimulant medication, non-stimulant medication, and psychosocial treatments are thoroughly reviewed. For each class of medication possible mechanism of action, efficacy and side effects are summarized. Special attention is given to the pharmacological treatment for patients with adult ADHD and various comorbidities. In summary, stimulant medications are most effective and combined medication and psychosocial treatment is the most beneficial treatment option for most adult patients with ADHD.
Collapse
Affiliation(s)
- Dusan Kolar
- Department of Psychiatry, Montreal Children's Hospital, McGill University Montreal, Canada
| | | | | | | | | | | |
Collapse
|
47
|
Cumyn L, Kolar D, Keller A, Hechtman L. Current issues and trends in the diagnosis and treatment of adults with ADHD. Expert Rev Neurother 2007; 7:1375-90. [PMID: 17939773 DOI: 10.1586/14737175.7.10.1375] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) has been commonly thought of as a childhood disorder that diminished over time. It is one of the most common developmental disorders and it is estimated that ADHD affects 5-10% of children. Two-thirds of children with ADHD will continue to have symptoms of ADHD that persist throughout adolescence. Longitudinal studies have demonstrated that symptoms of ADHD can also remain in adulthood, affecting 4.4% of the adult population. However, diagnosing adults with ADHD can prove difficult because they often find that their symptoms are egosyntonic. In addition, the development of comorbid conditions, such as anxiety, depression, personality disorders or substance abuse, can often overshadow underlying ADHD symptoms. Nonetheless, treatments such as stimulant and nonstimulant medication (e.g., atomoxetine), and cognitive-behavior therapy have been effective in treating adults with ADHD. This article reviews the prevalence of adults with ADHD, followed by a discussion of the neurobiological and genetic underpinnings of the disorder. Issues regarding the diagnosis and treatment of ADHD are also addressed.
Collapse
Affiliation(s)
- Lucy Cumyn
- McGill University, Department of Educational & Counselling Psychology, 3700 McTavish St., Montreal, Quebec, H3A 1Y2.
| | | | | | | |
Collapse
|
48
|
Zhao SX, Dalvie DK, Kelly JM, Soglia JR, Frederick KS, Smith EB, Obach RS, Kalgutkar AS. NADPH-dependent covalent binding of [3H]paroxetine to human liver microsomes and S-9 fractions: identification of an electrophilic quinone metabolite of paroxetine. Chem Res Toxicol 2007; 20:1649-57. [PMID: 17907785 DOI: 10.1021/tx700132x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The primary pathway of clearance of the methylenedioxyphenyl-containing compound and selective serotonin reuptake inhibitor paroxetine in humans involves P450 2D6-mediated demethylenation to a catechol intermediate. The process of demethylenation also results in the mechanism-based inactivation of the P450 isozyme. While the link between P450 2D6 inactivation and pharmacokinetic interactions of paroxetine with P450 2D6 substrates has been firmly established, there is a disconnect in terms of paroxetine's excellent safety record despite the potential for bioactivation. In the present study, we have systematically assessed the NADPH-dependent covalent binding of [(3)H]paroxetine to human liver microsomes and S-9 preparations in the absence and presence of cofactors of the various phase II drug-metabolizing enzymes involved in the downstream metabolism/detoxification of the putative paroxetine-catechol intermediate. Incubation of [(3)H]paroxetine with human liver microsomes and S-9 preparations resulted in irreversible binding of radioactive material to macromolecules by a process that was NADPH-dependent. The addition of reduced glutathione (GSH) to the microsomal and S-9 incubations resulted in a dramatic reduction of covalent binding. Following incubations with NADPH- and GSH-supplemented human liver microsomes and S-9, three sulfydryl conjugates with MH(+) ions at 623 Da (GS1), 779 Da (GS2), and 928 Da (GS3), respectively, were detected by LC-MS/MS. The collision-induced dissociation spectra allowed an insight into the structure of the GSH conjugates, based on which, bioactivation pathways were proposed. The formation of GS 1 was consistent with Michael addition of GSH to the quinone derived from two-electron oxidation of paroxetine-catechol. GS 3 was formed by the addition of a second molecule of GSH to the quinone species obtained via the two-electron oxidation of GS 1. The mechanism of formation of GS 2 can be rationalized via (i) further two-electron oxidation of the catechol motif in GS 3 to the ortho-quinone, (ii) loss of a glutamic acid residue from one of the adducted GSH molecules, and (iii) condensation of a cysteine-NH 2 with an adjacent carbonyl of the ortho-quinone to yield an ortho-benzoquinoneimine structure. Inclusion of the catechol-O-methyltransferase cofactor S-adenosylmethionine (SAM) in S-9 incubations also dramatically reduced the covalent binding of [(3)H]paroxetine, a finding that was consistent with O-methylation of the paroxetine-catechol metabolite to the corresponding guaiacol regioisomers in S-9 incubations. While the NADPH-dependent covalent binding was attenuated by GSH and SAM, these reagents did not alter paroxetine's ability to inactivate P450 2D6, suggesting that the reactive intermediate responsible for P450 inactivation did not leave the active site to react with other proteins. The results of our studies indicate that in addition to the low once-a-day dosing regimen (20 mg) of paroxetine, efficient scavenging of the catechol and quinone metabolites by SAM and GSH, respectively, serves as an explanation for the excellent safety record of paroxetine despite the fact that it undergoes bioactivation.
Collapse
Affiliation(s)
- Sabrina X Zhao
- Pharmacokinetics, Dynamics and Metabolism Department, Pfizer Global Research and Development, Groton, Connecticut, USA
| | | | | | | | | | | | | | | |
Collapse
|
49
|
van der Lee MJ, Blenke AAM, Rongen GA, Verwey-van Wissen CPWGM, Koopmans PP, Pharo C, Burger DM. Interaction study of the combined use of paroxetine and fosamprenavir-ritonavir in healthy subjects. Antimicrob Agents Chemother 2007; 51:4098-104. [PMID: 17846135 PMCID: PMC2151442 DOI: 10.1128/aac.01243-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus-infected patients have an increased risk for depression. Despite the high potential for drug-drug interactions, limited data on the combined use of antidepressants and antiretrovirals are available. Theoretically, ritonavir-boosted protease inhibitors may inhibit CYP2D6-mediated metabolism of paroxetine. We wanted to determine the effect of fosamprenavir-ritonavir on paroxetine pharmacokinetics and vice versa and to evaluate the safety of the combination. Group A started with 20 mg paroxetine every day for 10 days; after a wash-out period of 16 days, subjects received paroxetine (20 mg every day) plus fosamprenavir-ritonavir (700/100 mg twice a day) from days 28 to 37. Group B received the regimens in reverse order. On days 10 and 37, pharmacokinetic curves were recorded. Twenty-six healthy subjects (18 females, 8 males) were included. Median (range) age and weight were 44.4 (18.2 to 64.3) years and 68.8 (51.0 to 89.4) kg. Three subjects were excluded (two because of adverse events; one for nonadherence). Addition of fosamprenavir-ritonavir to paroxetine resulted in a significant decrease in paroxetine exposure: the geometric mean ratios (90% confidence intervals) of paroxetine plus fosamprenavir-ritonavir to paroxetine alone were 0.45 (0.41 to 0.49) for the area under the concentration-time curve from 0 to 24 h (AUC(0-24)), 0.49 (0.45 to 0.53) for the maximum concentration of the drug in plasma (C(max)), and 0.75 (0.71 to 0.80) for the apparent elimination half-life (t(1/2)). The free fraction of paroxetine showed a median (interquartile range) increase of 30% (18 to 42%) after the addition of fosamprenavir-ritonavir. The AUC(0-12), C(max), C(min), and t(1/2) of amprenavir and ritonavir were similar to those of historical controls. No serious adverse events occurred. Fosamprenavir-ritonavir reduced total paroxetine exposure by 55%. This is partly explained by protein displacement of paroxetine. We think that this interaction is clinically relevant and that titration to a higher dose of paroxetine may be necessary to accomplish the needed antidepressant effect.
Collapse
Affiliation(s)
- Manon J van der Lee
- Department of Clinical Pharmacy, Radboud University Medical Centre Nijmegen, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
50
|
Guo W, Li W, Guo G, Zhang J, Zhou B, Zhai Y, Wang C. Determination of atomoxetine in human plasma by a high performance liquid chromatographic method with ultraviolet detection using liquid–liquid extraction. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 854:128-34. [PMID: 17509951 DOI: 10.1016/j.jchromb.2007.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 03/29/2007] [Accepted: 04/03/2007] [Indexed: 11/28/2022]
Abstract
A HPLC method with UV detection (210 nm) was developed and validated for the quantification of atomoxetine, a new medication for the treatment of attention deficit/hyperactivity disorder, in human plasma. Following a two-step liquid-liquid extraction with diethyl ether, the analyte and internal standard (maprotiline) were separated using an isocratic mobile phase of acetonitrile/phosphate buffer (39/61, v/v, pH 6.6) on a reverse phase Inertsil C(18) column. Linearity was verified over the range of 3.12-200 ng/mL atomoxetine in plasma. The lowest limit of detection is 2.5 ng/mL (S/N=10). This HPLC method was validated with within- and between-batch precisions of 4.9-14.4% and 4.7-13.1%, respectively. The within- and between-batch biases were -1.9 to 1.4% and 0.1-13.8%, respectively. Commonly used psychotropic drugs and frequently coadministered drugs did not interfere with the drug and internal standard. This method is simple, economical and specific, and has been used successfully in a pharmacokinetic study of atomoxetine.
Collapse
Affiliation(s)
- Wei Guo
- Laboratory of Clinical Psychopharmacology, Beijing Anding Hospital, Capital Medical University, AnKang Lane 5#, Deshengmen Wai, Xicheng District, Beijing 100088, China
| | | | | | | | | | | | | |
Collapse
|