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Rančić A, Milosavljević MN, Rosić N, Milovanović D, Folić M, Zečević DR, Petrović N, Čorbić MM, Dabanović V, Janković SM. Population pharmacokinetics of meropenem in critically ill patients. Open Med (Wars) 2024; 19:20241004. [PMID: 39070942 PMCID: PMC11278387 DOI: 10.1515/med-2024-1004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 05/11/2024] [Accepted: 07/08/2024] [Indexed: 07/30/2024] Open
Abstract
Objective The pharmacokinetics of meropenem are significantly altered in critically ill patients. A population pharmacokinetic study was designed to estimate typical values of meropenem clearance in critically ill patients and evaluate potential factors of influence. Methods After meropenem reached a steady state in each patient, two blood samples were taken within the dose interval. The one-compartment pharmacokinetic model based on the data from 101 intensive care unit patients was built using NONMEM software. Results Typical values of meropenem clearance and volume of distribution were 3.80 L/h and 3.52 L, respectively. In the final model, meropenem clearance was influenced by serum concentrations of creatinine (CRE), leukocyte count (WBC), hypertension (HTA), and concomitant use of vancomycin (VAN) or colistimethate (COL): CL (L/h) = 5.29 × CRE ^ 0.000001 × WBCs ^ (-0.165) + 0.000001 × HTA + 0.825 × VAN + 1.28 × COL. Conclusion In order to achieve effective plasma concentrations of meropenem in critically ill patients, the meropenem dosing regimen should be adjusted according to individual values of drug clearance.
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Affiliation(s)
| | - Miloš N. Milosavljević
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, Kragujevac, 34000, Serbia
| | - Nikola Rosić
- Clinical Pharmacology Department, University Clinical Centre Kragujevac, Kragujevac, Serbia
| | - Dragan Milovanović
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, Kragujevac, 34000, Serbia
| | - Marko Folić
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, 34000, Serbia
| | - Dejana Ružić Zečević
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, Kragujevac, 34000, Serbia
- Clinical Pharmacology Department, University Clinical Centre Kragujevac, Kragujevac, Serbia
| | - Nemanja Petrović
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, Kragujevac, 34000, Serbia
- Clinical Pharmacology Department, University Clinical Centre Kragujevac, Kragujevac, Serbia
| | | | - Vera Dabanović
- Pharmacy Institution of Montenegro “Montefarm”, Podgorica, Montenegro
| | - Slobodan M. Janković
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, Kragujevac, 34000, Serbia
- Clinical Pharmacology Department, University Clinical Centre Kragujevac, Kragujevac, Serbia
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Lukic V, Jankovic SM, Petrovic NZ, Vucinic S, Jovic Stosic J, Djordjevic S, Dragojevic-Simić V. Population toxicokinetics of carbamazepine and its metabolite carbamazepine-10,11-epoxide in adults. Expert Opin Drug Metab Toxicol 2024:1-9. [PMID: 39021252 DOI: 10.1080/17425255.2024.2381555] [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: 03/21/2024] [Accepted: 06/15/2024] [Indexed: 07/20/2024]
Abstract
BACKGROUND Carbamazepine is one of the most commonly used antiseizure medications. Although carbamazepine pharmacokinetics in epileptic patients is well described, much less is known about these processes in the patients who experienced self-poisoning episode by this drug. Therefore, the aim of our investigation was to perform population toxicokinetics of carbamazepine and its metabolite carbamazepine-10,11-epoxide in adults. RESEARCH DESIGN AND METHODS Software program NONMEM and the ADVAN2 TRANS2 subroutine were used for establishing a population toxicokinetic model for the estimation of clearance and volume of distribution based on of the sum values of carbamazepine and carbamazepine-10,11-epoxide concentrations. RESULTS Our results indicated that the adult patients' ability to eliminate carbamazepine and carbamazepine-10,11-epoxide following acute carbamazepine self-poisoning was strongly associated with the high levels of CRP and ASP, as well as by the treatment with sedation. CONCLUSIONS Our study should provide better understanding of the toxicokinetics of carbamazepine taken in overdose and better management of patient population admitted to hospital.
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Affiliation(s)
- Vladan Lukic
- National Poison Control Centre, Military Medical Academy, Belgrade, Serbia
- Medical Faculty of the Military Medical Academy, University of Defence, Belgrade, Serbia
| | - Slobodan M Jankovic
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Clinical Pharmacology, University Clinical Center Kragujevac, Kragujevac, Serbia
| | - Nemanja Z Petrovic
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Clinical Pharmacology, University Clinical Center Kragujevac, Kragujevac, Serbia
| | - Slavica Vucinic
- National Poison Control Centre, Military Medical Academy, Belgrade, Serbia
- Medical Faculty of the Military Medical Academy, University of Defence, Belgrade, Serbia
| | - Jasmina Jovic Stosic
- National Poison Control Centre, Military Medical Academy, Belgrade, Serbia
- Medical Faculty of the Military Medical Academy, University of Defence, Belgrade, Serbia
| | - Snezana Djordjevic
- National Poison Control Centre, Military Medical Academy, Belgrade, Serbia
- Medical Faculty of the Military Medical Academy, University of Defence, Belgrade, Serbia
| | - Viktorija Dragojevic-Simić
- Medical Faculty of the Military Medical Academy, University of Defence, Belgrade, Serbia
- Centre for Clinical Pharmacology, Military Medical Academy, Belgrade, Serbia
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Hertz DL, Arwood MJ, Stocco G, Singh S, Karnes JH, Ramsey LB. Planning and Conducting a Pharmacogenetics Association Study. Clin Pharmacol Ther 2021; 110:688-701. [PMID: 33880756 DOI: 10.1002/cpt.2270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/04/2021] [Indexed: 12/13/2022]
Abstract
Pharmacogenetics (PGx) association studies are used to discover, replicate, and validate the association between an inherited genotype and a treatment outcome. The objective of this tutorial is to provide trainees and novice PGx researchers with an overview of the major decisions that need to be made when designing and conducting a PGx association study. The first critical decision is to determine whether the objective of the study is discovery, replication, or validation. Next, the researcher must identify a patient cohort that has all of the data necessary to conduct the intended analysis. Then, the investigator must select and define the treatment outcome, or phenotype, that will be analyzed. Next, the investigator must determine what genotyping approach and genetic data will be included in the analysis. Finally, the association between the genotype and phenotype is tested using some statistical analysis methodology. This tutorial is divided into five sections; each section describes commonly used approaches and provides suggestions and resources for designing and conducting a PGx association study. Successful PGx association studies are necessary to discover and validate associations between inherited genetic variation and treatment outcomes, which enable clinical translation to improve efficacy and reduce toxicity of treatment.
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Affiliation(s)
- Daniel L Hertz
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, Michigan, USA
| | - Meghan J Arwood
- Tabula Rasa HealthCare, Precision Pharmacotherapy Research and Development Institute, Orlando, Florida, USA
| | - Gabriele Stocco
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Sonal Singh
- Takeda California, San Diego, California, USA
| | - Jason H Karnes
- Department of Pharmacy Practice and Science, University of Arizona College of Pharmacy, Tucson, Arizona, USA.,Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Laura B Ramsey
- Divisions of Clinical Pharmacology & Research in Patient Services, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Zhou H. Population-Based Assessments of Clinical Drug-Drug Interactions: Qualitative Indices or Quantitative Measures? J Clin Pharmacol 2013; 46:1268-89. [PMID: 17050792 DOI: 10.1177/0091270006294278] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Population-based assessments of drug-drug interactions have become more common since the introduction and acceptance of the population pharmacokinetic approach. Unlike traditional methods, population-based studies provide clinically relevant results that can be applied directly to a target patient population. Furthermore, population-based studies do not demand the traditional requirements of intensive pharmacokinetic sampling, rigorous inpatient stays, or stringent assessment schedules. As such, the population-based approach can effectively be used to confirm known drug-drug interactions and further characterize anticipated interactions. A prospectively designed analysis can also reveal drug-drug interactions that might otherwise have gone undetected with traditional methods. Ultimately, these results could help to alleviate clinicians' concerns about using widely marketed drugs in combination therapies and also reduce patients' risk of experiencing unacceptable side effects. This article intends to provide a balanced overview of the population-based approach and its merits, drawbacks, and potential utility in the assessment of drug-drug interactions during clinical drug development.
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Affiliation(s)
- Honghui Zhou
- Pharmacokinetics, Modeling & Simulation, Clinical Pharmacology & Experimental Medicine, Centocor Research & Development, Malvern, PA 19087, USA
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Zhou H, Mayer PR, Wajdula J, Fatenejad S. Unaltered Etanercept Pharmacokinetics With Concurrent Methotrexate in Patients With Rheumatoid Arthritis. J Clin Pharmacol 2013; 44:1235-43. [PMID: 15496641 DOI: 10.1177/0091270004268049] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to evaluate the potential impact of concurrent weekly oral methotrexate administration on the pharmacokinetics of etanercept in patients with rheumatoid arthritis (RA) in a phase 3B trial. As part of a double-blind randomized trial of 682 patients with rheumatoid arthritis who received etanercept (25 mg subcutaneously twice weekly), methotrexate (weekly oral dose, median weekly dose: 20 mg), or etanercept (25 mg subcutaneously twice weekly) plus methotrexate (weekly oral dose, median weekly dose: 20 mg), serum etanercept concentrations were measured in a subset of patients. Serum samples for 98 randomly selected patients (48 receiving etanercept-alone treatment, 50 receiving etanercept plus methotrexate combination treatment) were analyzed to assess the pharmacokinetics of etanercept. A single blood sample was drawn from each patient at baseline and at the week 24 visit. Given the variable sampling time for patients in both groups, a population pharmacokinetic analysis using NONMEM was conducted for etanercept. A final covariate population pharmacokinetic model was constructed based on previously obtained etanercept data from both healthy subjects (n = 53) and patients with RA (n = 212) in 10 prior clinical trials. The predictive performance of the final model was assessed by both bootstrap and data-splitting validation approaches. The final model was then used to estimate Bayesian pharmacokinetic parameters for the patients in both treatments in the current trial. The potential effect of the concurrent administration of methotrexate on the pharmacokinetics of etanercept was examined by comparing the clearance values between 2 treatments using statistical criteria. A population 2-compartment model with first-order elimination from the central compartment and with either zero-order (intravenous administration) or first-order (subcutaneous administration) input was selected based on the data from the prior 10 etanercept clinical studies. The following pharmacokinetic parameters (typical value +/- standard error) were estimated: clearance (CL: 0.072 +/- 0.005 L/h), volume of distribution in the central compartment (V(c): 5.97 +/- 0.45 L), volume of distribution in the peripheral compartment (V(p): 2.05 +/- 0.32 L), intercompartment clearance (Q: 0.0645 +/- 0.0093 L/h), first-order absorption rate constant (k(a): 0.0282 +/- 0.0039 1/h), and absolute bioavailability for subcutaneous administration (F: 0.626 +/- 0.056). Interindividual variability of the pharmacokinetic parameters was quantified for CL (25.1%), V(c) (41.7%), k(a) (53.1%), and F (24.2%). Residual variability consisted of combined additive (11.4 ng/mL) and proportional error (49.9%). Both age (< 17 years) and body weight (< 60 kg) were found to be important covariates on CL. The results of both validation tests indicated the adequate predictive performance of the population model. Based on the bioequivalence criteria, the Bayesian-estimated clearance for patients receiving etanercept alone (mean: 0.070 L/h) was comparable to that for patients receiving a combination of etanercept and methotrexate (mean = 0.066 L/h). The pharmacokinetics of etanercept were not altered by the concurrent administration of methotrexate in patients with rheumatoid arthritis. Thus, no etanercept dose adjustment is needed for patients taking concurrent methotrexate.
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Affiliation(s)
- Honghui Zhou
- Clinical Pharmacology, Wyeth Research, 500 Arcola Road, Collegeville, PA 19426, USA
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Ueshima S, Aiba T, Sato T, Matsunaga H, Kurosaki Y, Ohtsuka Y, Sendo T. Empirical Approach for Improved Estimation of Unbound Serum Concentrations of Valproic Acid in Epileptic Infants by Considering Their Physical Development. Biol Pharm Bull 2011; 34:108-13. [DOI: 10.1248/bpb.34.108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Satoshi Ueshima
- Department of Hospital Pharmacy, Okayama University Hospital
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Tetsuya Aiba
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Tomoaki Sato
- Department of Hospital Pharmacy, Okayama University Hospital
| | - Hisashi Matsunaga
- Department of Hospital Pharmacy, Okayama University Hospital
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Yuji Kurosaki
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Yoko Ohtsuka
- Department of Child Neurology, Okayama University Hospital
| | - Toshiaki Sendo
- Department of Hospital Pharmacy, Okayama University Hospital
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
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Jakovljević MB, Janković SM, Todorović N, Milovanović JR, Janković S. [Pharmacokinetic modelling of valproate in epileptic patients]. MEDICINSKI PREGLED 2010; 63:349-55. [PMID: 21186545 DOI: 10.2298/mpns1006349j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION The aim of our study was to develop and use a population pharmacokinetic model for assessment of individual valproate clearance in children and young adults suffering from epilepsy. MATERIAL AND METHODS The analysis was performed using 52 steady-state concentrations of valproate collected from 26 epileptic patients during the routine clinical practice in our hospital. The mean values of age and total body weight were 19.92 years and 57.12 kg, respectively. NONMEM software with ADVAN 1 subroutine was used for model building and assessing the influence of different covariates. A validation set of 20 epileptic patients (one blood sample per a patient) was used to estimate predicted performances of the pharmacokinetic model. RESULTS The typical mean value of the clearance of valproate estimated by the base model in our population was 0.3 77 I/h. Out of five considered covariates (total body weight, age, total daily dose, gender and polytherapy) only the age of the patients was a significant determinant of the clearance of valproate. The final regression model for the clearance of valproate was as following: CL (l/h) = 0.223 + 0.00819 * AGE CONCLUSION: The derived pharmacokinetical model describes the clearance of valproate in relation to patient's age in the observed population. it will help to improve the seizure control in young patients with epilepsy in Serbian population.
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Yamazaki S, Toth LN, Kimoto E, Bower J, Skaptason J, Romero D, Heath TG. Application of stable isotope methodology in the evaluation of the pharmacokinetics of (S,S)-3-[3-(methylsulfonyl)phenyl]-1-propylpiperidine hydrochloride in rats. Drug Metab Dispos 2009; 37:937-45. [PMID: 19237512 DOI: 10.1124/dmd.108.025478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The primary objective of this study was to demonstrate the use of stable isotope (SI)-labeled compound as an approach for pharmacokinetic analysis such as fraction absorbed, hepatic extraction ratio, and fraction metabolized from the parent drug to a metabolite. (S,S)-3-[3-(Methylsulfonyl)phenyl]-1-propylpiperidine hydrochloride (PNU96391) was selected as the model compound because of its simple biotransformation pathway, i.e., the predominant metabolic pathway to the N-despropyl metabolite (M1), which makes it a suitable candidate. The second objective was to fully characterize the pharmacokinetics of PNU96391 in rats using the SI coadministration approach with quantitative analysis by liquid chromatography-tandem mass spectrometry. Overall the present study showed that 1) absorption of PNU96391 from the gastrointestinal tract was near complete (>90% of the dose), 2) PNU96391 was predominantly metabolized to M1 (approximately 70% of the dose), and 3) M1 was exclusively eliminated into urine with negligible biotransformation (ratio of renal clearance to plasma clearance approximately 0.9). Therefore, the present study demonstrated the utility of the SI methodology for characterizing the pharmacokinetics of a compound within the drug discovery and development process. Furthermore, the compartmental pharmacokinetic modeling provided insights into the disposition and biotransformation rates of PNU96391 and M1, suggesting that the modeling could add further advantages to the SI coadministration approach. Despite the greater availability of SI-labeled compounds, absorption, distribution, metabolism, and excretion (ADME) scientists have yet to take full advantage of the potential use of these analogs for mechanistic ADME studies. These SI-labeled compounds can be used more widely to gain a better understanding of ADME properties in drug discovery and development.
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Affiliation(s)
- Shinji Yamazaki
- Pharmacokinetics, Dynamics and Metabolism, La Jolla Laboratories, Pfizer Global Research and Development, 10777 Science Center Dr., San Diego, CA 92121, USA.
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Lötsch J, Harder S, Stürmer M, Doerr HW, Geisslinger G, Staszewski S, von Hentig N. Association of saquinavir plasma concentrations with side effects but not with antiretroviral outcome in patients infected with protease inhibitor-susceptible human immunodeficiency virus type 1. Antimicrob Agents Chemother 2007; 51:3264-72. [PMID: 17576836 PMCID: PMC2043227 DOI: 10.1128/aac.00036-07] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 04/27/2007] [Accepted: 06/11/2007] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to identify parameters among saquinavir pharmacokinetics, patients' demographics or comedications, to be addressed for improved personalized therapy. The presence of human immunodeficiency virus type 1 (HIV-1) RNA at therapy week 48 (principal target parameter), CD4 cell count at week 48, infections and side effects during 48 weeks, indicators of liver toxicity and lipid abnormalities at week 48, and a 12-h saquinavir plasma concentration-versus-time profile were assessed in 56 patients receiving saquinavir-ritonavir (1,000 and 100 mg, respectively) twice daily (44 therapy-naïve and 12 antiretrovirally pretreated patients) for association with saquinavir plasma concentrations, demographics, baseline values of target parameters, and coadministered antiretrovirals. Antiretroviral failure was observed in 8 of the 56 patients in whom HIV-1 RNA was detectable at week 48. This therapeutic failure was not associated with individual saquinavir pharmacokinetics. More likely, therapeutic failure was related to incidences interfering with antiretroviral therapy, causing therapy interruptions or incompliance. Weak associations were, however, seen between high maximum saquinavir plasma concentrations and both CD4 counts of > or =200 cells microl(-1) at week 48 (P = 0.014) and constitutional side effects during 48 weeks (P = 0.002). However, patients with high CD4 counts and constitutional side effects were not identical (P = 0.53). Saquinavir therapeutic drug monitoring in patients infected with protease inhibitor-susceptible HIV-1 taking saquinavir-ritonavir (1,000 and 100 mg, respectively) is not demanded for improving the antiretroviral effect. It may be contemplated in cases with constitutional side effects or low CD4 counts with weak immune responses.
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Affiliation(s)
- Jörn Lötsch
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany.
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Lim KS, Kwon JS, Jang IJ, Jeong JM, Lee JS, Kim HW, Kang WJ, Kim JR, Cho JY, Kim E, Yoo SY, Shin SG, Yu KS. Modeling of Brain D2 Receptor Occupancy-Plasma Concentration Relationships with a Novel Antipsychotic, YKP1358, Using Serial PET Scans in Healthy Volunteers. Clin Pharmacol Ther 2007; 81:252-8. [PMID: 17259948 DOI: 10.1038/sj.clpt.6100049] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
YKP1358 is a novel serotonin (5-HT(2A)) and dopamine (D(2)) antagonist that, in preclinical studies, fits the general profile of an atypical antipsychotic. We conducted a D(2) receptor occupancy study with YKP1358 in healthy volunteers using positron emission tomography (PET) to measure the D(2) receptor occupancy of YKP1358 and to characterize its relationship to plasma drug concentrations. A single oral dose, parallel group, dose-escalation (100, 200, and 250 mg) study was performed in 10 healthy male volunteers with the PET radiotracer [(11)C]raclopride. The D(2) receptor occupancy of striatum was measured pre-dose, and at 2, 5, and 10 h after YKP1358 administration. Serial blood samples were taken for measurement of plasma YKP1358 concentrations. D(2) receptor occupancy by YKP1358 increased to 53-83% at 2 h, and then decreased afterwards, ranging from 40-64% at 5 h to 20-51% at 10 h. The YKP1358 dose-plasma concentration relationship exhibited extensive variability, but there was a good relationship between plasma concentrations and D(2) receptor occupancy that was well predicted by a sigmoid E(max) model using nonlinear mixed effects modeling. To our knowledge, this is the first study in which the relationship between plasma concentration and the biomarker of D(2) receptor occupancy was modeled using nonlinear mixed effects modeling. It is anticipated that these results will be useful in estimating for subsequent studies the initial doses of YKP1358 required to achieve a therapeutically effective range of D(2) receptor occupancy.
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Affiliation(s)
- K S Lim
- Department of Pharmacology and Clinical Pharmacology Unit, Seoul National University College of Medicine and Hospital, Seoul, Korea
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Lotrich FE, Bies R, Muldoon MF, Manuck SB, Smith GS, Pollock BG. Neuroendocrine response to intravenous citalopram in healthy control subjects: pharmacokinetic influences. Psychopharmacology (Berl) 2005; 178:268-75. [PMID: 15365685 DOI: 10.1007/s00213-004-2006-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE The neuroendocrine response to intravenous citalopram may provide an acute, functional, in vivo measure of the neural serotonin (5-HT) system. OBJECTIVE To refine the quantification of acute neuroendocrine responses following intravenous citalopram in studies of 5-HT function. METHODS In 75 adult healthy subjects taking part in four similar protocols, we measured plasma prolactin and cortisol, as well as serial citalopram concentrations following intravenous citalopram (10 mg, 20 mg, 40 mg, 0.33 mg/kg) and placebo. The relationship between the AUC for intravenous citalopram during the first 150 min (AUC(150)) and the magnitude of the neuroendocrine response was determined. The role of pharmacokinetic (PK) parameters, as well as sensitivity to placebo injections, in influencing the neuroendocrine response to citalopram was then evaluated. RESULTS Citalopram produced a dose-dependent increase in cortisol and prolactin. The maximal increase from baseline correlated significantly but modestly with citalopram's AUC(150) (prolactin r(2)=0.23, P<0.0001; cortisol r(2)=0.3, P<0.0001). Additionally, citalopram's AUC(150) was affected by between-subject differences in both the peripheral and central volume of distribution. However, the neuroendocrine responses to citalopram did not correlate with the responses to placebo. CONCLUSIONS The parenteral citalopram challenge test is characterized by a modest concentration-response relationship, with concentration influenced by variable PK factors. Accounting for individual differences in drug distribution may improve the power of the citalopram challenge test, when used as an in vivo measure of central 5-HT function.
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Affiliation(s)
- Francis E Lotrich
- Department of Psychiatry, Western Psychiatric Institute and Clinic, Pittsburgh, PA, USA.
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