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Davis MP, McPherson ML, Reddy A, Case AA. Conversion ratios: Why is it so challenging to construct opioid conversion tables? J Opioid Manag 2024; 20:169-179. [PMID: 38700396 DOI: 10.5055/jom.0853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Standardizing opioid management is challenging due to the absence of a ceiling dose, the unknown ideal therapeutic plasma level, and the lack of an clear relationship between dose and therapeutic response. Opioid rotation or conversion, which is switching from one opioid, route of administration, or both, to another, to improve therapeutic response and reduce toxicities, occurs in 20-40 percent of patients treated with opioids. Opioid conversion is often needed when there are adverse effects, toxicities, or inability to tolerate a certain opioid formulation. A majority of patients benefit from opioid conversion, leading to improved analgesia and less adverse effects. There are different published ways of converting opioids in the literature. This review of 20 years of literature is centered on opioid conversions and aims to discuss the complexity of converting opioids. We discuss study designs, outcomes and measures, pain phenotypes, patient characteristics, comparisons of equivalent doses between opioids, reconciling conversion ratios between opioids, routes, directional differences, half-lives and metabolites, interindividual variability, and comparison to package insert information. Palliative care specialists have not yet come to a consensus on the ideal opioid equianalgesic table; however, we discuss a recently updated table, based on retrospective evidence, that may serve as a gold standard for practical use in the palliative care population. More robust, well-designed studies are needed to validate and guide future opioid conversion data.
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Affiliation(s)
- Mellar P Davis
- Geisinger Medical Center, Danville, Pennsylvania. ORCID: https://orcid.org/0000-0002-7903-3993
| | - Mary Lynn McPherson
- University of Maryland School of Pharmacy, Baltimore, Maryland. ORCID: https://orcid.org/0000-0001-6098-2112
| | - Akhila Reddy
- Department of Palliative, Rehabilitation, and Integrative Medicine, The University of Texas MD Anderson Cancer, Houston, Texas. ORCID: https://orcid.org/0000-0002-7628-8675
| | - Amy A Case
- Department of Palliative and Supportive Care, Roswell Park Comprehensive Cancer Center, Buffalo, New York
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2
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Wallace B, Edwardes D, Subbe C, Murtaza M. Interaction between methadone and clarithromycin as the suspected cause of an opioid toxidrome. Drug Ther Bull 2023; 61:12-15. [PMID: 36008097 DOI: 10.1136/dtb.2022.240647rep] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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3
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Mawatari H, Shinjo T, Morita T, Kohara H, Yomiya K. Revision of Pharmacological Treatment Recommendations for Cancer Pain: Clinical Guidelines from the Japanese Society of Palliative Medicine. J Palliat Med 2022; 25:1095-1114. [PMID: 35363057 DOI: 10.1089/jpm.2021.0438] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Pain is one of the most common symptoms in cancer patients. The Japanese Society for Palliative Medicine (JSPM) first published its clinical guidelines for the management of cancer pain in 2010. Since then, more research on cancer pain management has been reported, and new drugs have become available in Japan. Thus, the JSPM has now revised the clinical guidelines using a validated methodology. Methods: This guideline was developed through a systematic review, discussion, and the Delphi method, following a formal guideline development process. Results: Thirty-five recommendations were created: 19 for the pharmacological management of cancer pain, 6 for the management of opioid-induced adverse effects, and 10 for pharmacological treatment procedures. Due to the lack of evidence that directly addressed our clinical questions, most of the recommendations had to be based on consensus among committee members and other guidelines. Discussion: It is critical to continue to build high-quality evidence in cancer pain management, and revise these guidelines accordingly.
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Affiliation(s)
- Hironori Mawatari
- Department of Palliative and Supportive Care, Yokohama Minami Kyosai Hospital, Yokohama City, Japan
| | - Takuya Shinjo
- Department of Palliative Medicine, Shinjo Clinic, Kobe City, Japan
| | - Tatsuya Morita
- Department of Palliative and Supportive Care, Seirei Mikatahara General Hospital, Hamamatsu City, Japan
| | - Hiroyuki Kohara
- Department of Palliative Medicine, Hiroshima Prefectural Hospital, Hiroshima City, Japan
| | - Kinomi Yomiya
- Department of Palliative Care, Saitama Cancer Center, Ina-machi, Japan
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Ghaderi-Bafti F, Zarghami M, Ahmadi A, Moosazadeh M, Hadinezhad P, Hendouei N. Effectiveness and Safety of Haloperidol Add-on Methadone in Acute Opium Withdrawal Symptoms of Opioid-dependent Patients: A Double-blind Randomized Placebo-controlled Clinical Trial. ADDICTION & HEALTH 2021; 13:85-94. [PMID: 34703529 PMCID: PMC8519612 DOI: 10.22122/ahj.v13i2.287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/08/2021] [Indexed: 11/16/2022]
Abstract
Background The aim of this double-blind clinical trial was to evaluate the efficacy and safety of haloperidol on acute opioid withdrawal symptoms. Methods In this randomized double-blind clinical trial, fifty-two eligible patients were assigned to two groups according to previous opioid consumption, low dose (LD) and high dose (HD). Then, patients in each group were randomly assigned to one of the two subgroups of haloperidol or placebo. Patients in the haloperidol subgroup in LD group received 2.5 mg and in HD group received 5 mg/day haloperidol with methadone. Methadone was discontinued ten days after the beginning of the study and haloperidol or placebo continued for up to two weeks after methadone discontinuation. The severity of opioid withdrawal symptoms was assessed with the Objective Opioid Withdrawal Scale (OOWS) every other day. Findings Although both treatment protocols either in LD or HD opioid consumption groups significantly increased the score of the OOWS over the trial period (all subgroups, P < 0.001), the combination of 2.5 mg/day of haloperidol and methadone in LD opioid consumption group showed a significant superiority over methadone alone in decreasing opium withdrawal symptoms during the study (P = 0.001). The frequency of adverse effects was comparable between two treatment protocols in both groups (P > 0.050). Conclusion The results of this study suggest that 2.5 mg/day of haloperidol may be an effective adjuvant agent in the management of opium withdrawal symptoms in patients with LD opioid consumption. Nevertheless, results of larger controlled trials are needed before recommendation for a broad clinical application can be made.
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Affiliation(s)
- Fattaneh Ghaderi-Bafti
- Department of Psychiatry, School of Medicine, Shahroud University of Medical Sciences, Shahroud AND Student Research Committee, Department of Psychiatry, School of Medicine AND Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mehran Zarghami
- Student Research Committee, Department of Psychiatry, School of Medicine AND Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Abdolkarim Ahmadi
- Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahmood Moosazadeh
- Gastrointestinal Cancer Research Center, Non-communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Pezhman Hadinezhad
- Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Narjes Hendouei
- Department of Clinical Pharmacy, School of Pharmacy AND Psychiatry and Behavioral Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
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5
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Daptomycin Pharmacokinetics and Pharmacodynamics in Patients on Methadone Substitution Therapy. Eur J Drug Metab Pharmacokinet 2021; 46:547-554. [PMID: 34231117 DOI: 10.1007/s13318-021-00690-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND AND OBJECTIVE When administered for severe infections in intravenous drug users (IDUs) at a daily dose of 6 mg/kg, daptomycin displayed abnormal pharmacokinetic parameters compared with those seen in healthy volunteers; specifically, decreased trough and maximum concentrations (Ctrough; Cmax) and increased clearance (CL). The objective of this study was to evaluate the pharmacokinetics and pharmacodynamics of daptomycin administered at a daily dosage of 12 mg/kg for Staphylococcus aureus infective endocarditis (IE) in patients concomitantly treated with methadone, and to compare the results with those published in the literature for healthy controls treated with the same daily dose. METHODS Antibiotic treatment included daptomycin (12 mg/kg daily) in combination with an antistaphylococcal β-lactam (cefazolin 2 g three times a day). The minimum inhibitory concentration (MIC) of Staphylococcus aureus isolated through blood cultures was used to calculate pharmacokinetic and pharmacodynamic parameters such as the ratio of the area under the concentration-time curve over 24 h to the MIC (AUC0-24/MIC) and Cmax/MIC. RESULTS Five IDUs hospitalized for IE were enrolled. The mean measured daptomycin Cmax and Ctrough were 54.1 μg/mL (CV: 0.32) and 8.7 μg/mL (CV: 0.59), respectively; the mean calculated AUC0-24 was 742.7 μg × h/mL (CV: 0.31). The estimated average volume of distribution at the steady state (Vd,ss) and the half-life (t1/2) were 316.5 mL/kg (CV: 0.53) and 14.4 h (CV: 0.30), respectively. The mean daptomycin clearance from plasma normalized for body weight (CLwp) was 17.3 mL/(h × kg) (CV: 0.33). The calculated average Cmax and AUC0-24 (183.7 µg/mL and 1277.4 µg × h/mL, respectively) were lower than and statistically significantly different from (p < 0.001 and p = 0.001, respectively) those expected for healthy volunteers. CONCLUSIONS Treatment of Staphylococcus aureus IE in IDUs on methadone treatment requires the use of high daptomycin daily doses in order to achieve satisfactory pharmacodynamic parameters. Close monitoring of the daptomycin plasma concentration is suggested.
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Wallace B, Edwardes D, Subbe C, Murtaza M. Interaction between methadone and clarithromycin as the suspected cause of an opioid toxidrome. BMJ Case Rep 2021; 14:14/5/e240647. [PMID: 34035018 PMCID: PMC8154935 DOI: 10.1136/bcr-2020-240647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A 40-year-old patient was admitted through the acute medical take with pleuritic chest pain and rigours. He had a medical history of opiate dependence and was receiving 60 mg of methadone once daily. He was diagnosed with a community-acquired pneumonia and treated with amoxicillin and clarithromycin. After administration of only two concomitant doses of methadone and oral clarithromycin, he developed an opioid toxidrome with type-2 respiratory failure, a decreased level of consciousness and pinpoint pupils. The patient was treated with naloxone and his symptoms improved. Retrospectively, it was suspected that an interaction between clarithromycin and methadone might have contributed to the toxidrome. Respiratory failure has not been previously prescribed for this combination of medication and is of high importance for physicians and pharmacists around the world.
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7
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Lee C, Wanson A, Frangou S, Chong D, Halpape K. Opioid toxicity due to CNS depressant polypharmacy: A case report. Ment Health Clin 2021; 11:70-74. [PMID: 33850686 PMCID: PMC8019539 DOI: 10.9740/mhc.2021.03.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The interaction between methadone and central nervous system depressants can cause serious adverse effects, including profound sedation, respiratory depression, coma, and death. This poses a challenge in the treatment of patients with concurrent psychiatric and substance use disorders as the combined use is often unavoidable. We report a case of a patient with opioid use disorder, mood disorder unspecified, chronic pain, and chronic obstructive pulmonary disease who experienced 2 serious episodes of CNS and respiratory depression due to polypharmacy-induced opioid toxicity. Careful consideration of pharmacokinetics, pharmacodynamics, and patient-specific factors was imperative to identify the suspected contributing medications: methadone, lorazepam, divalproex, gabapentin, and cyclobenzaprine. Cognitive and system factors that contributed to these adverse events and strategies to mitigate risk of recurrence were also identified.
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Affiliation(s)
- Christine Lee
- BSP Candidate 2020, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Annabelle Wanson
- Assistant Professor, Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Sarah Frangou
- Psychiatry PGY-5, Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - David Chong
- Psychiatry PGY-5, Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Katelyn Halpape
- Assistant Professor, College of Pharmacy and Nutrition, University of Saskatchewan 2A20.01 Health Sciences, Saskatoon, Saskatchewan, Canada,
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8
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A Review of the Metabolism and Potential Drug-drug Interactions With Addictive Drugs. J Addict Med 2021; 16:e30-e39. [PMID: 33606425 DOI: 10.1097/adm.0000000000000824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
People who use drugs (PWUD) are at increased risk for drug-related harms such as overdose. Additionally, they are also at increased risk of secondary harms from bacterial and other infections such as hepatitis B, hepatitis C, and Human Immunodeficiency Virus. These secondary harms, along with other medical conditions, typically require treatment with prescription medications. When considering treatment options, drug-drug interactions (DDIs) must be considered, unfortunately these interactions are often overlooked with addictive drugs. Although DDIs in PWUD have been reviewed for certain drug classes and specific drugs of abuse, no comprehensive list could be found. The objective of this article is to compile a list of potential DDIs between prescription drugs and addictive drugs to create a list allowing prescribers to make more informed decisions when prescribing a medication to PWUD.
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9
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Li YP, Yang Y, Wang MQ, Zhang X, Wang WJ, Li M, Wu FP, Dang SS. Facial and bilateral lower extremity edema due to drug-drug interactions in a patient with hepatitis C virus infection and benign prostate hypertrophy: A case report. World J Clin Cases 2020; 8:3372-3376. [PMID: 32874995 PMCID: PMC7441249 DOI: 10.12998/wjcc.v8.i15.3372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/07/2020] [Accepted: 07/16/2020] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND New direct-acting antivirals (DAAs)-based anti-hepatitis C virus (HCV) therapies are highly effective in patients with HCV infection. However, safety data are lacking regarding HCV treatment with DAAs and drugs for comorbidities.
CASE SUMMARY Herein, we reported a case of HCV-infection in a 46-year-old man with benign prostatic hypertrophy. The patient received sofosbuvir/velpatasvir as well as methadone maintenance therapy for drug abuse. The viral load became negative at week 1 post treatment. He developed facial and bilateral lower extremity edema 48 h after starting receiving tamsulosin. Edema disappeared 10 d after treatment with oral furosemide and spironolactone.
CONCLUSION In conclusion, this is the first case of an acute edema in the course of treatment with new DAAs, methadone and tamsulosin. These agents are useful in clinical management of patients with HCV infection, particularly in men with benign prostatic hypertrophy. Clinicians should be aware of potential drug-drug interactions in this subset of patients.
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Affiliation(s)
- Ya-Ping Li
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Ying Yang
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Mu-Qi Wang
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Xin Zhang
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Wen-Jun Wang
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Mei Li
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Feng-Ping Wu
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
| | - Shuang-Suo Dang
- Department of Infectious Diseases, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
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10
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González-Barboteo J, Porta-Sales J, Nabal-Vicuña M, Díez-Porres L, Canal-Sotelo J, Alonso-Babarro A, Vílches-Aguirre Y, Pérez-Pujol S, Sanllorente M, Llorens-Torromé S, Gómez-Batiste Alentorn X, Bruera E. Switching Ratio from Parenteral to Oral Methadone 1:1.2 Is Safer Compared with Ratio 1:2 in Patients with Controlled Cancer Pain: A Multicenter Randomized-Controlled Trial (RATIOMTD-010810). J Palliat Med 2020; 24:382-390. [PMID: 32749916 DOI: 10.1089/jpm.2020.0244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: The most commonly used switching ratio from parenteral to oral methadone is 1:2. Methadone is highly bioavailable and a lower ratio might result in similar analgesia with less toxicity. Objective: To compare success and side effects with two ratios from parenteral to oral methadone: 1:2 versus 1:1.2 in hospitalized patients with cancer pain. Design: A multicenter double-blind randomized clinical trial. Settings/Particiants: Inpatients with well-controlled cancer pain with parenteral methadone requiring rotation to the oral route. Measurements: Outcomes included pain intensity (Brief Inventory Pain), opioid toxicity (Common Toxicology Criteria for Adverse Events), and methadone dose. Success was defined as no toxicity with good pain control at 72 hours. Results: Thirty-nine of forty-four randomized patients were evaluable: 21 in ratio 1:2 and 18 in ratio 1:1.2. Seventy-one percent male. Median age 65 years. No significant differences in basal clinical characteristics between both groups. Median methadone dose pre/post switching was 24.5 mg ±13.5 and 49 mg ±27.3 for ratio 1:2, versus 23.3 mg ±9.4 (p: not significant) and 28 mg ±11.3 (p < 0.01) for ratio 1:1.2. Pain was well controlled without differences between both ratios. Drowsiness at day +1 (p < 0.017) and myoclonus at day +3 (p < 0.019) were more prevalent in group 1:2. Success was observed in 12 patients in ratio 1:2 versus 18 in ratio 1:1.2 (p < 0.001). Methadone side effects were observed in 12 patients in ratio 1:2 (mainly neurotoxicity symptoms) versus 2 in ratio 1:1.2 (p < 0.005). Conclusion: Ratio 1:1.2 when changing from parenteral to oral methadone resulted in lower toxicity and no difference in analgesia. More conservative dose adjustment during methadone route change should be considered. European Clinical Trials Register (EudraCT No. 2010-024092-39).
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Affiliation(s)
- Jesús González-Barboteo
- Palliative Care Department, Hospital Duran i Reynals, Catalan Institute of Oncology, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Josep Porta-Sales
- Bellvitge Biomedical Research Institute (IDIBELL), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.,Support and Palliative Care Service, Hospital Universitari de Girona Dr. Josep Trueta, Girona, Spain.,Palliative Care Research, Institut Català d'Oncologia, Girona, Spain.,WeCare: End of Life Care Chair, Medicine and Health Sciences School, Universitat Internacional de Catalunya, Barcelona, Spain.,Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - María Nabal-Vicuña
- Supportive Palliative Care Team, Hospital Universitari Arnau de Vilanova, Lleida, Spain
| | - Leyre Díez-Porres
- Palliative Care Department, Hospital Universitario La Paz, Madrid, Spain
| | - Jaume Canal-Sotelo
- Supportive Palliative Care Team, Hospital Universitari Santa Maria, Lleida, Spain
| | | | | | - Silvia Pérez-Pujol
- Clinical Research and Clinical Trials Unit (UICEC), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Mireia Sanllorente
- Clinical Research and Clinical Trials Unit (UICEC), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Silvia Llorens-Torromé
- Palliative Care Department, Hospital Duran i Reynals, Catalan Institute of Oncology, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Xavier Gómez-Batiste Alentorn
- Palliative Care Department, Hospital Duran i Reynals, Catalan Institute of Oncology, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Bellvitge Biomedical Research Institute (IDIBELL), Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.,Qualy Observatory, WHO Collaborating Center for Palliative Care Public Health Programs, Catalan Institute of Oncology, Barcelona, Spain.,Department of Palliative Care, University of Vic, Vic, Spain
| | - Eduardo Bruera
- Department of Palliative Care and Rehabilitation Medicine, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,UT Graduate School of Biomedical Sciences at Houston, Houston, Texas, USA
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11
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Packiasabapathy S, Aruldhas BW, Horn N, Overholser BR, Quinney SK, Renschler JS, Sadhasivam S. Pharmacogenomics of methadone: a narrative review of the literature. Pharmacogenomics 2020; 21:871-887. [PMID: 32705966 DOI: 10.2217/pgs-2020-0040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background: Methadone, a synthetic opioid with longer duration of action and lower abuse potential compared with morphine, is used to prevent opioid withdrawal, as well as to manage chronic and acute surgical pain. The variability in response to methadone has been widely recognized. The purpose of this article is to review the literature on the pharmacogenetic factors underlying this variability. Materials & methods: This is a narrative overview of the literature on the genetic variants affecting pharmacodynamics and pharmacokinetics of methadone, retrieved from searches of databases such as PubMed and google scholar. Discussion: Clinical responses to methadone may be affected by genetic variants in the opioidergic, dopaminergic and neurotrophic pathways. Polymorphisms in genes related to disposition and elimination of methadone alter the pharmacokinetics, and possibly pharmacodynamics of methadone. Cytochrome P450 enzymes and P-glycoprotein variants contribute to the interindividual variability in methadone pharmacokinetics. Evidence for single gene variants affecting methadone response remains weak. Multiple genetic variants must be considered in conjunction to improve predictive ability. Conclusion: Evidence remains scarce at this time, to recommend pharmacogenetic testing before methadone administration. Well-powered clinical studies are needed with population pharmacokinetic-pharmacodynamic modeling and multigenetic signature-based predictions to enable tailored use of methadone in clinical practice.
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Affiliation(s)
- Senthil Packiasabapathy
- Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Blessed W Aruldhas
- Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Pharmacology & Clinical Pharmacology, Christian Medical College, Vellore, 632002, India
| | - Nicole Horn
- Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brian R Overholser
- Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Pharmacy Practice, Purdue University College of Pharmacy, Indianapolis, IN 47907, USA
| | - Sara K Quinney
- Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Obstetrics & Gynecology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Center for Computational Biology & Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Janelle S Renschler
- Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Senthilkumar Sadhasivam
- Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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12
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Kelty E, Hulse G, Joyce D, Preen DB. Impact of Pharmacological Treatments for Opioid Use Disorder on Mortality. CNS Drugs 2020; 34:629-642. [PMID: 32215842 DOI: 10.1007/s40263-020-00719-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of pharmacological treatments for opioid use disorders, including methadone, buprenorphine and naltrexone has been associated with a reduction in mortality compared with illicit opioid use. However, these treatments can also contribute significantly to the risk of death. The opioid agonists methadone and buprenorphine achieve clinical efficacy in patients with an opioid use disorder through suppressing craving and diminishing the effectiveness of illicit opioid doses, while the antagonist naltrexone blocks the action of opioids. Pharmacological differences between opioid pharmacotherapies then create different temporal patterns of protection and mortality risk, different risks of relapse to illicit opioid use, and variations in direct and indirect toxicity, which are revealed in clinical and epidemiological studies. Induction onto methadone and the cessation of oral naltrexone treatment are associated with an elevated risk of opioid poisoning, which is not apparent in patients treated with buprenorphine or sustained-release naltrexone. Beyond drug-related mortality, these pharmacotherapies can impact a participant's risk of death. Buprenorphine may also have some advantages over methadone in patients with depressive disorders or cardiovascular abnormalities. Naltrexone, which is also commonly prescribed to manage problem alcohol use, may reduce deaths in chronic co-alcohol users. Understanding these pharmacologically driven patterns then guides the judicious choice of drug and dosing schedule and the proactive risk management that is crucial to minimising the risk of death in treatment.
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Affiliation(s)
- Erin Kelty
- School of Population and Global Health, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA, 6009, Australia.
| | - Gary Hulse
- Division of Psychiatry, Medical School, The University of Western Australia, Perth, WA, Australia.,Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - David Joyce
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - David B Preen
- School of Population and Global Health, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA, 6009, Australia
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Abstract
OPINION STATEMENT The opioid epidemic is one of the most important public health crises as opioid-related deaths have become a leading cause of accidental death in the USA. Various efforts have been made to understand how to safely and appropriately prescribe opioids for patients with chronic pain, including those with cancer-related pain. We find the guidelines proposed by the Expert Consensus White Paper on the use of methadone to be current, comprehensive, and practical. While methadone is a complex medication with unique pharmacokinetics and pharmacodynamics, it remains a superior choice for many patients with cancer pain given its cost and applicability in a variety of situations. Methadone should be prescribed in the context of experienced clinicians as well as an interdisciplinary team. At a critical time when preventing opioid-related deaths is a priority, we recommend implementing additional precautions for monitoring including universal screening for risk of non-medical opioid use, education on proper storage and disposal, as well as discussing a plan with patients and caregivers in the case of serious complications such as opioid overdose.
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Affiliation(s)
- Yvonne Heung
- Department of Palliative Care, Rehabilitation, and Integrative Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1414, Houston, TX, 77030, USA
| | - Akhila Reddy
- Department of Palliative Care, Rehabilitation, and Integrative Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1414, Houston, TX, 77030, USA.
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Treillet E, Laurent S, Hadjiat Y. Practical management of opioid rotation and equianalgesia. J Pain Res 2018; 11:2587-2601. [PMID: 30464578 PMCID: PMC6211309 DOI: 10.2147/jpr.s170269] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Purpose To review the recent literature on opioid rotation (ie, switching from one opioid drug to another or changing an opioid’s administration route) in cancer patients experiencing severe pain and to develop a novel equianalgesia table for use in routine clinical practice. Methods The MEDLINE database was searched with terms “cancer pain,” “opioid rotation,” “opioid switching,” “opioid ratio,” “opioid conversion ratio,” and “opioid equianalgesia” for the major opioids (morphine, oxycodone, fentanyl, and hydromorphone) and the intravenous, subcutaneous, oral, and transdermal administration routes. Selected articles were assessed for the calculated or cited opioid dose ratio, bidirectionality, and use of the oral morphine equivalent daily dose or a direct drug-to-drug ratio. Results Twenty publications met our selection criteria and were analyzed in detail. We did not find any large-scale, prospective, double-blind randomized controlled trial with robust design, and most of the studies assessed relatively small numbers of patients. Bidirectionality was investigated in seven studies only. Conclusion The updated equianalgesic table presented here incorporates the latest data and provides information on bidirectionality. Despite the daily use of equianalgesic tables, they are not based on high-level scientific evidence. More clinical research is needed on this topic.
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Affiliation(s)
- Erwan Treillet
- AP-HP, Médecine de la Douleur et Médecine Palliative, Hôpital Lariboisière, Paris, France,
| | - Sophie Laurent
- Institut de Cancérologie, Institut Gustave Roussy, Villejuif, France
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Abstract
Recently, the opioid analgesic d,l-methadone has gained much attention as a potential antineoplastic compound, considerably triggered through lay press and media. In consequence, physicians and pharmacists are currently confronted with numerous patients willing to use d,l-methadone against their malignancies. Well-performed in vitro and in vivo models have in fact shown pro-apoptotic effects of d,l-methadone or other opioids, but also proliferation-stimulating properties. Moreover, the mechanisms of proposed opioid-stimulated apoptosis are incompletely described or contradicting. Finally, the receptors mostly responsible for induction of apoptosis by d,l-methadone remain unclear as contributions of both µ-opioid receptors, Fas cell death receptors, toll-like receptors, N-Methyl-d-aspartate receptors and opioid growth factor receptors were suggested. Such ambiguity prevents rational application of d,l-methadone or patient stratification to enhance beneficial antineoplastic effects. From a clinical point of view, d,l-methadone and other opioids might in fact prolong survival, but such effects likely originate from their analgesic and neuro-psychotropic properties and, thus, improvements of quality of life. Crucial obstacles to the administration of d,l-methadone are incomplete knowledge about its systemic disposition, highly variable pharmacokinetics, profound drug-drug- or drug-disease interaction and QT-prolongation potential. This article summarizes and rates the pharmacological basis of d,l-methadone as an antineoplastic agent and puts its administration in clinical oncology into perspective. Despite enthralling experimental findings about d,l-methadone-mediated apoptosis in cancerous cells or tissues, clinicians should realize the current lack of evidence for the use of d,l-methadone as an antineoplastic agent. Its administration against cancer pain is, however, tenable, albeit restricted to certain clinical situations.
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Affiliation(s)
- Dirk Theile
- Department of Clinical Pharmacology and Pharmacoepidemiology, University Hospital Heidelberg, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany
| | - Gerd Mikus
- Department of Clinical Pharmacology and Pharmacoepidemiology, University Hospital Heidelberg, Im Neuenheimer Feld 410, Heidelberg, 69120, Germany
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16
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Mercadante S, Bruera E. Methadone as a First-Line Opioid in Cancer Pain Management: A Systematic Review. J Pain Symptom Manage 2018; 55:998-1003. [PMID: 29101087 DOI: 10.1016/j.jpainsymman.2017.10.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/24/2017] [Accepted: 10/24/2017] [Indexed: 10/18/2022]
Abstract
AIM The objective of this review was to assess the existent evidence for the use of methadone as a first-line therapy in cancer pain management. METHODS A systematic literature search on MEDLINE and Embase databases was carried out from each database, setting up the date to August 30, 2017. Studies were included if methadone was a first-line drug as a Step 3 of World Health Organization analgesic ladder, or at low doses (Step 2), if they were conducted in adult patients with cancer pain, and if they contained outcomes on pain- and opioid-related adverse effects. RESULTS The initial search yielded 219 records. Ten articles were considered after the initial screening according to inclusion and exclusion criteria. They included three longitudinal open-label studies. In two studies methadone was initiated at low doses (≤10 mg/day). These studies suggested that methadone was effective in providing analgesia and well tolerated as first opioid at different starting doses and in different conditions and settings. Five additional studies were randomized controlled studies with morphine in patients who had received opioids for moderate pain. Methadone, compared with oral morphine, or transdermal fentanyl, either at low (Step 2 level) or relatively higher doses (Step 3 level), provided similar analgesia with similar adverse effects profile with limited dose escalation in time. CONCLUSION Available data are not sufficient to draw net conclusion. However, open-label and controlled studies have shown that methadone may be effective as first-line drug in the management of cancer pain, providing analgesia and adverse effect profiles similar to those produced by other opioids. The finding that methadone doses tend to remain stable suggests that metabolic characteristics and extraopioid analgesic effects, as its well antihyperalgesic properties may be interesting potential advantages. Further studies should provide information regarding the long-term use of methadone or the need to switch from methadone to other opioids when a loss of analgesic response occurs.
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Affiliation(s)
- Sebastiano Mercadante
- Department of Palliative Care and Rehabilitation Medicine, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA.
| | - Eduardo Bruera
- Department of Palliative Care and Rehabilitation Medicine, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
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17
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Methadone as anticancer treatment: hype, hope, or hazard? Wien Med Wochenschr 2018; 168:159-167. [DOI: 10.1007/s10354-018-0623-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/25/2018] [Indexed: 01/23/2023]
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18
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Michalska M, Katzenwadel A, Wolf P. Methadone as a "Tumor Theralgesic" against Cancer. Front Pharmacol 2017; 8:733. [PMID: 29163148 PMCID: PMC5671505 DOI: 10.3389/fphar.2017.00733] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/28/2017] [Indexed: 12/24/2022] Open
Abstract
Methadone has beneficial characteristics as an analgesic against cancer pain, including high bioavailability, multiple receptor affinities, and lack of active metabolites that might induce adverse side effects. However, methadone has an own pharmacological profile that should be considered in the treatment of cancer patients. There is evidence from preclinical studies that methadone could also elicit antitumor activity by downregulating the threshold of apoptosis and to enhance the effects of different chemotherapeutic agents. This confirms the concept of using methadone as a chemosensitizer in the future treatment of cancer. Our article discusses major issues about the role of methadone as a possible “tumor theralgesic,” combining tumor therapeutic and analgesic activities.
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Affiliation(s)
- Marta Michalska
- Department of Urology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Arndt Katzenwadel
- Department of Urology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Wolf
- Department of Urology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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19
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Juba KM, Khadem TM, Hutchinson DJ, Brown JE. Methadone and Corrected QT Prolongation in Pain and Palliative Care Patients: A Case-Control Study. J Palliat Med 2017; 20:722-728. [PMID: 28186837 DOI: 10.1089/jpm.2016.0411] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Methadone (ME) is commonly used in pain and palliative care (PPC) patients with refractory pain or intolerable opioid adverse effects (AEs). A unique ME AE is its corrected QT (QTc) interval prolongation risk, but most evidence exists in methadone maintenance therapy patients. OBJECTIVE Our goal was to identify QTc interval prolongation risk factors in PPC patients receiving ME and other medications known to prolong the QTc interval and develop a risk stratification tool. DESIGN We performed a case-control study of adult inpatients receiving ME for pain management. Settings/Subjects: Adult inpatients receiving ME with a QTc >470 msec (males) and >480 msec (females) were matched 1:2 according to age, history of QTc prolongation, and gender with ME patients who did not have a prolonged QTc interval. QTc prolongation risk factors were collected for both groups. Covariates were analyzed using conditional logistic regression. Classification and regression tree analysis was used to identify the ME dose associated with QTc prolongation. RESULTS Predictors of QTc prolongation included congestive heart failure (CHF) (OR: 11.9; 95% CI: 3.7-38.2; p < 0.00), peptic ulcer disease (PUD) (odds ratio [OR]: 8.3; 95% confidence interval [95% CI]: 2.4-28.9; p < 0.00), hypokalemia (OR: 6.5; 95% CI: 1.5-28.2; p < 0.01), rheumatologic diseases (OR: 4.7; 95% CI: 1.6-13.9; p < 0.00), taking medications with a known torsades de pointes (TdP) risk (OR: 4.4; 95% CI: 1.8-10.7; p < 0.01), malignancy (OR: 3.3; 95% CI: 1.2-9.3; p < 0.03), hypocalcemia (OR: 2.1; 95% CI: 0.9-4.8; p < 0.07), and ME doses >45 mg per day (OR: 1.9; 95% CI: 0.8-4.8; p < 0.16). Mild liver disease was protective against QTc prolongation (OR: 0.05; 95% CI: 0.0-0.46; p < 0.01). CONCLUSIONS Predictors of QTc prolongation in our multivariate conditional logistic regression model included CHF, PUD, hypokalemia, rheumatologic disorders, use of medications with a known TdP risk, malignancy, hypocalcemia, and ME doses >45 mg per day.
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Affiliation(s)
- Katherine M Juba
- 1 Department of Pharmacy Practice, Wegmans School of Pharmacy, St. John Fisher College , Rochester, New York
| | - Tina M Khadem
- 2 Department of Pharmacy, University of Rochester Medical Center-Strong Memorial Hospital , Rochester, New York
| | - David J Hutchinson
- 1 Department of Pharmacy Practice, Wegmans School of Pharmacy, St. John Fisher College , Rochester, New York
| | - Jack E Brown
- 1 Department of Pharmacy Practice, Wegmans School of Pharmacy, St. John Fisher College , Rochester, New York
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20
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Abstract
BACKGROUND This is an updated review originally published in 2004 and first updated in 2007. This version includes substantial changes to bring it in line with current methodological requirements. Methadone is a synthetic opioid that presents some challenges in dose titration and is recognised to cause potentially fatal arrhythmias in some patients. It does have a place in therapy for people who cannot tolerate other opioids but should be initiated only by experienced practitioners. This review is one of a suite of reviews on opioids for cancer pain. OBJECTIVES To determine the effectiveness and tolerability of methadone as an analgesic in adults and children with cancer pain. SEARCH METHODS For this update we searched CENTRAL, MEDLINE, Embase, CINAHL, and clinicaltrials.gov, to May 2016, without language restriction. We also checked reference lists in relevant articles. SELECTION CRITERIA We sought randomised controlled trials comparing methadone (any formulation and by any route) with active or placebo comparators in people with cancer pain. DATA COLLECTION AND ANALYSIS All authors agreed on studies for inclusion. We retrieved full texts whenever there was any uncertainty about eligibility. One review author extracted data, which were checked by another review author. There were insufficient comparable data for meta-analysis. We extracted information on the effect of methadone on pain intensity or pain relief, the number or proportion of participants with 'no worse than mild pain'. We looked for data on withdrawal and adverse events. We looked specifically for information about adverse events relating to appetite, thirst, and somnolence. We assessed the evidence using GRADE and created a 'Summary of findings' table. MAIN RESULTS We revisited decisions made in the earlier version of this review and excluded five studies that were previously included. We identified one new study for this update. This review includes six studies with 388 participants. We did not identify any studies in children.The included studies differed so much in their methods and comparisons that no synthesis of results was feasible. Only one study (103 participants) specifically reported the number of participants with a given level of pain relief, in this case a reduction of at least 20% - similar in both the methadone and morphine groups. Using an outcome of 'no worse than mild pain', methadone was similar to morphine in effectiveness, and most participants who could tolerate methadone achieved 'no worse than mild pain'. Adverse event withdrawals with methadone were uncommon (12/202) and similar in other groups. Deaths were uncommon except in one study where the majority of participants died, irrespective of treatment group. For specific adverse events, somnolence was more common with methadone than with morphine, while dry mouth was more common with morphine than with methadone. None of the studies reported effects on appetite.We judged the quality of evidence to be low, downgraded due to risk of bias and sparse data. For specific adverse events, we considered the quality of evidence to be very low, downgraded due to risk of bias, sparse data, and indirectness, as surrogates for appetite, thirst and somnolence were used.There were no data on the use of methadone in children. AUTHORS' CONCLUSIONS Based on low-quality evidence, methadone is a drug that has similar analgesic benefits to morphine and has a role in the management of cancer pain in adults. Other opioids such as morphine and fentanyl are easier to manage but may be more expensive than methadone in many economies.
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Affiliation(s)
| | - Graeme R Watson
- South Tees Hospitals NHS Foundation TrustMiddlesbroughUKTS4 3BW
| | - Sheena Derry
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Pain Research UnitChurchill HospitalOxfordOxfordshireUKOX3 7LE
| | - Philip J Wiffen
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Pain Research UnitChurchill HospitalOxfordOxfordshireUKOX3 7LE
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21
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Ogbuagu O, Friedland G, Bruce RD. Drug interactions between buprenorphine, methadone and hepatitis C therapeutics. Expert Opin Drug Metab Toxicol 2016; 12:721-31. [DOI: 10.1080/17425255.2016.1183644] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | - R. Douglas Bruce
- Yale University School of Medicine, New Haven, CT, USA
- Department of Medicine, Cornell Scott-Hill Health Center, New Haven, CT, USA
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22
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Mouly S, Bloch V, Peoc'h K, Houze P, Labat L, Ksouda K, Simoneau G, Declèves X, Bergmann JF, Scherrmann JM, Laplanche JL, Lepine JP, Vorspan F. Methadone dose in heroin-dependent patients: role of clinical factors, comedications, genetic polymorphisms and enzyme activity. Br J Clin Pharmacol 2016; 79:967-77. [PMID: 25556837 DOI: 10.1111/bcp.12576] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/05/2014] [Accepted: 12/21/2014] [Indexed: 01/11/2023] Open
Abstract
AIMS Methadone is characterized by wide intersubject variability regarding the dose needed to obtain full therapeutic response. We assessed the influence of sociodemographic, ethnic, clinical, metabolic and genotypic variables on methadone maintenance dose requirement in opioid-dependent responder patients. METHODS Eighty-one stable patients (60 men and 21 women, 43.7 ± 8.1 years old, 63.1 ± 50.9 mg day(-1) methadone), divided into quartiles with respect to the median daily dose, were enrolled and underwent clinical examination, treatment history and determination of liver/intestinal cytochrome P450 (CYP) 3A4 activity measured by the midazolam test, R,S-methadone trough concentration and clinically significant polymorphisms of the OPRM1, DRD2, COMT, ABCB1, CYP2B6, CYP3A5, CYP2C19 and CYP2D6 genes. RESULTS Methadone maintenance dose was correlated to the highest dose ever used (r(2) = 0.57, P < 0.0001). Fractioned methadone intake (odds ratio 4.87, 95% confidence interval 1.27-18.6, P = 0.02), bodyweight (odds ratio 1.57, 95% confidence interval 1.01-2.44, P = 0.04), history of cocaine dependence (80 vs. 44 mg day(-1) in never-addict patients, P = 0.005) and ethnicity (Asian > Caucasian > African, P = 0.04) were independently associated with high-dose methadone in multiple regression analysis. A modest correlation was observed between liver/intestinal CYP3A4 activity and methadone dose at steady state (Spearman rank correlation coefficient [rs ] = 0.21, P = 0.06) but not with highest dose ever used (rs = 0.15, P = 0.18) or dose-normalized R,S-methadone trough concentrations (rs = -0.05, P = 0.64). Concomitant CYP3A4 inhibitors only affected the relationship between methadone dose and R,S-methadone trough concentration. None of the genetic polymorphisms explored was predictive of the methadone maintenance dose. CONCLUSIONS Methadone maintenance dose was predicted by sociodemographic and clinical variables rather than genetic polymorphisms or liver/intestinal CYP3A4 activity in stable patients.
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Affiliation(s)
- Stéphane Mouly
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Unit of Therapeutic Research & Internal Medicine Department, Lariboisière-Saint Louis Hospital, Paris, France
| | - Vanessa Bloch
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France
| | - Katell Peoc'h
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Laboratory of Biochemistry and Molecular Biology, Lariboisière-Saint Louis Hospital, Paris, France
| | - Pascal Houze
- Laboratory of Pharmacology, Lariboisière-Saint Louis Hospital, Paris, France
| | - Laurence Labat
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France
| | - Kamilia Ksouda
- Psychiatric Unit, Assistance Publique-Hôpitaux de Paris (APHP), Lariboisière-Saint Louis Hospital, Paris, France
| | - Guy Simoneau
- Unit of Therapeutic Research & Internal Medicine Department, Lariboisière-Saint Louis Hospital, Paris, France
| | - Xavier Declèves
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France
| | - Jean Francois Bergmann
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Unit of Therapeutic Research & Internal Medicine Department, Lariboisière-Saint Louis Hospital, Paris, France
| | - Jean-Michel Scherrmann
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France
| | - Jean-Louis Laplanche
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Laboratory of Biochemistry and Molecular Biology, Lariboisière-Saint Louis Hospital, Paris, France
| | - Jean-Pierre Lepine
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Psychiatric Unit, Assistance Publique-Hôpitaux de Paris (APHP), Lariboisière-Saint Louis Hospital, Paris, France
| | - Florence Vorspan
- Inserm, U1144, Paris, F-75006, France.,Université Paris Descartes, UMR-S1144, Paris, F-75006, France.,Université Paris Diderot, UMR-S1144, Paris, F-75010, France.,Psychiatric Unit, Assistance Publique-Hôpitaux de Paris (APHP), Lariboisière-Saint Louis Hospital, Paris, France
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23
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Mercadante S. Opioid metabolism and clinical aspects. Eur J Pharmacol 2015; 769:71-8. [DOI: 10.1016/j.ejphar.2015.10.049] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/14/2015] [Accepted: 10/27/2015] [Indexed: 12/16/2022]
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24
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Meini M, Moncini M, Daini L, Giarratana T, Scaramelli D, Chericoni S, Stefanelli F, Rucci P. Relationship between plasma concentrations of the l-enantiomer of methadone and response to methadone maintenance treatment. Eur J Pharmacol 2015; 760:1-6. [PMID: 25891369 DOI: 10.1016/j.ejphar.2015.03.081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 03/20/2015] [Accepted: 03/27/2015] [Indexed: 10/23/2022]
Abstract
This study evaluated the relationship between the plasma concentration of l-methadone and response to methadone in real-world patients, in order to identify a minimum plasma concentration above which methadone treatment is effective. Ninety-four patients with opioid dependence under maintenance methadone treatment were consecutively recruited. Response was defined as negative urine analyses in the three weeks prior to the blood sampling. The percentage of participants with a plasma l-methadone concentration between 100 and 250 ng/ml was 54.2% among those with a methadone dosage ≥60 mg/day. Plasma l-methadone concentrations were significantly higher in patients with negative urine analyses compared with those with positive urine analyses (median 93 vs. 77 ng/ml, Mann-Whitney test, P<0.05). Above plasma l-methadone concentrations of 200 ng/ml no heroin use was reported and urine analyses were negative. Moreover, above concentrations of 250 ng/ml craving was absent. Examination of demographic correlates of treatment outcome indicated that older age, a stable job and being married were protective against the use of heroin. Mean plasma l-methadone concentration was significantly lower in patients who used cannabis compared with those who did not use cannabis, after adjusting for methadone dosage. In conclusion our results identify specific cut-offs for plasma l-methadone concentrations about which therapeutic response is observed and provide new evidence that therapeutic response is associated with patient׳s demographic characteristics. This underscores the need to monitor plasma methadone concentrations as part of Drug Addiction Services routine practice, in order to provide an objective framework for changing the methadone dosage.
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Affiliation(s)
- Milo Meini
- Department of Drug Addiction Medicine, Local Health Authority of Pisa, Italy
| | - Marco Moncini
- Department of Drug Addiction Medicine, Local Health Authority of Pisa, Italy
| | - Laura Daini
- Department of Drug Addiction Medicine, Local Health Authority of Pisa, Italy
| | - Tania Giarratana
- Department of Drug Addiction Medicine, Local Health Authority of Pisa, Italy
| | - Daniela Scaramelli
- Department of Drug Addiction Medicine, Local Health Authority of Pisa, Italy
| | - Silvio Chericoni
- Department of Surgical Pathology, Medical, Molecular and Critical Area, Section of Forensic Medicine, University of Pisa and University Hospital Trust, Pisa, Italy
| | - Fabio Stefanelli
- Department of Surgical Pathology, Medical, Molecular and Critical Area, Section of Forensic Medicine, University of Pisa and University Hospital Trust, Pisa, Italy
| | - Paola Rucci
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Via San Giacomo 12, 40126 Bologna, Italy.
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25
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Searby A, Maude P, McGrath I. An Ageing Methadone Population: A Challenge to Aged Persons' Mental Health Services? Issues Ment Health Nurs 2015; 36:927-31. [PMID: 26631866 DOI: 10.3109/01612840.2015.1081655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oral administration of methadone has been used as a treatment strategy for opiate addiction for many years. The state of Victoria, Australia, has a long-running methadone program with a large number of participants. Accordingly, a growing number of adults have utilised methadone maintenance treatment for a number of years and are now moving into older age due to advances in medical treatment and harm reduction initiatives. The objective of this review is to examine the literature pertaining to co-occurring mental illness in older methadone treatment participants and to explore the future challenges this growing cohort of ageing adults pose to aged persons’ psychiatry services. As part of a broader study into dual diagnosis in older adults, a search of the Scopus, ProQuest, and CINAHL journal databases was performed. Twenty abstracts from literature published within the previous 15 years (1999–2014) were identified that explored methadone maintenance programs and the older adults maintained on them. A number of researchers have identified the ageing methadone population to have a high degree of comorbid mental illness and psychological distress. Studies also indicate that individuals enrolled in methadone maintenance programs may engage in a degree of continual substance use, potentially leading to deleterious effects on their psychosocial function. An ageing methadone population experiencing a high degree of comorbid mental illness is likely to challenge aged persons’ psychiatry services. These services are likely to be increasingly called on to manage these individuals, particularly within Victoria where few substance use services exist for those over the age of 65. It is essential that aged persons’ psychiatry services prepare to provide care for these individuals in a responsive manner that is inclusive of both their mental health and substitution pharmacotherapy.
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Affiliation(s)
- Adam Searby
- a Alfred Health, Caulfield Hospital Mobile Aged Psychiatry Service , Caulfield , Australia , and RMIT University, School of Health Sciences , Bundoora , Australia
| | - Phil Maude
- b RMIT University, School of Health Sciences , Bundoora , Australia
| | - Ian McGrath
- b RMIT University, School of Health Sciences , Bundoora , Australia
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Eyler ECH. Chronic and acute pain and pain management for patients in methadone maintenance treatment. Am J Addict 2014; 22:75-83. [PMID: 23398230 DOI: 10.1111/j.1521-0391.2013.00308.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/01/2012] [Accepted: 08/20/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Many individuals receiving methadone maintenance treatment (MMT) for opioid addiction also require treatment for acute or chronic pain, and the presence of pain is known to have a negative impact on patient health and function. However, effective pain management in this population is complicated by many factors, including heightened pain sensitivity, high opioid tolerance, illicit substance use, and variable cross-tolerance to opioid pain medications. This article reviews the recent literature on acute and chronic pain among, and pain treatment of, patients receiving MMT for opioid addiction and discusses the implications for effective pain management. Acute pain management among women maintained on methadone during and after labor and delivery is also discussed, as well as common concerns held by patients and providers about appropriate pain management strategies in the context of methadone maintenance and addiction treatment. METHODS One hundred nine articles were identified in a PubMed/MEDLINE electronic database search using the following search terms: methadone, methadone maintenance, methadone addiction, pain, pain management, chronic pain, and acute pain. Abstracts were reviewed for relevance, and additional studies were extracted from the reference lists of articles identified in the original search. RESULTS The pain sensitivity and pain responses of MMT patients differ significantly from those of patients not maintained on opioids, and few data are available to guide patient care. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE Rigorous studies are needed to identify and evaluate effective pain management approaches for this unique patient population and to improve patient treatment outcomes.
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Affiliation(s)
- Elizabeth C H Eyler
- JBS International, Inc., 5515 Security Lane, Suite 800, North Bethesda, MD 20852, USA.
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Greenblatt DJ. Drug interactions with methadone: Time to revise the product label. Clin Pharmacol Drug Dev 2014; 3:249-51. [PMID: 27128829 DOI: 10.1002/cpdd.137] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 06/16/2014] [Indexed: 01/16/2023]
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Taberna M, Villavicencio-Chávez C, González-Barboteo J. [Use of methadone in the elderly with cancer pain: a systematic review]. Rev Esp Geriatr Gerontol 2014; 49:129-136. [PMID: 24457178 DOI: 10.1016/j.regg.2013.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/07/2013] [Accepted: 08/30/2013] [Indexed: 06/03/2023]
Abstract
OBJECTIVE To identify the clinical use of methadone as an analgesic in the management of cancer pain in elderly patients. MATERIAL AND METHODS We performed a systemic review of the literature on the specific use of methadone in elderly with cancer pain in MEDLINE, COCHRANE DATABASE and SCOPUS. A second search was conducted in MEDLINE to look for clinical trials and systematic review of the use of methadone in cancer pain, selecting only those in which the mean age of patients was ≥ 65 years old. RESULTS Four articles were obtained in the first search, and from the second 7 clinical trials, none of them specific to methadone use in elderly patients with cancer. CONCLUSIONS There are insufficient data on the use of methadone as an analgesic in the elderly with cancer. Given its pharmacological characteristics it must be used by trained personnel. Several recommendations are proposed for its use as an analgesic in the treatment of cancer pain in the elderly.
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Affiliation(s)
- Miren Taberna
- Servicio de Oncología Médica, Institut Català d́Oncologia, Hospital Duràn i Reynals, L'Hospitalet de Llobregat, Barcelona, España
| | - Christian Villavicencio-Chávez
- Servicio de Cuidados Paliativos, Institut Català d́Oncologia, Hospital Duràn i Reynals, L'Hospitalet de Llobregat, Barcelona, España; Grup de Cures Pal·liatives, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, España; Facultat de Medicina, Universitat Internacional de Catalunya, Barcelona, España
| | - Jesús González-Barboteo
- Servicio de Cuidados Paliativos, Institut Català d́Oncologia, Hospital Duràn i Reynals, L'Hospitalet de Llobregat, Barcelona, España; Grup de Cures Pal·liatives, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, España; Càtedra de Cures Pal·liatives-Centre d'Estudis Sanitaris i Socials, Universitat de Vic, Vic, España; Comisión de Oncogeriatría, Institut Català d́Oncologia, Hospital Duràn i Reynals, L'Hospitalet de Llobregat, Barcelona, España.
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Macey TA, Weimer MB, Grimaldi EM, Dobscha SK, Morasco BJ. Patterns of care and side effects for patients prescribed methadone for treatment of chronic pain. J Opioid Manag 2014; 9:325-33. [PMID: 24353045 DOI: 10.5055/jom.2013.0175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/12/2013] [Accepted: 07/23/2013] [Indexed: 11/05/2022]
Abstract
OBJECTIVES This manuscript evaluates physician monitoring practices and incidence of cardiac side effects following initiation of methadone for treatment of chronic pain as compared to patients who began treatment for chronic pain with morphine sustained release (SR). DESIGN We retrospectively reviewed medical record data on all new initiations of methadone and compared results of physician monitoring practices to patients with new initiations of morphine SR. A standardized chart tool was used to capture clinical data. Data related to health service utilization and clinical diagnoses were obtained from the VA clinical information system. SETTING A single VA Medical Center in the Pacific Northwest. PATIENTS Chronic pain patients prescribed methadone (n=92) or morphine (n=90) in the calendar year 2008. RESULTS There was no difference between patients prescribed methadone versus patients prescribed morphine SR in the likelihood of receiving an electrocardiogram (ECG) prior to initiating medication (53 percent versus 54 percent) or in the year after opioid initiation (37 percent versus 40 percent). The two groups also did not differ in rates of developing prolonged rate-corrected (QTc) intervals (>450 ms) (11 percent versus 17 percent). Seventy-two percent of all patients discontinued their long-acting opioid regimens before 90 days due to adverse effects or insufficient pain relief. CONCLUSION Despite recommendations for standardized assessment and cardiac risk monitoring, few patients prescribed methadone received an ECG, and this occurred at a rate that did not differ from patients prescribed morphine SR. Patients discontinued both medications at high rates. Further research is needed to evaluate the clinical significance of QTc prolongation in patients treated with methadone.
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Affiliation(s)
- Tara A Macey
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon
| | - Melissa B Weimer
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Elizabeth M Grimaldi
- Mental Health and Clinical Neurosciences Division, Portland VA Medical Center, Portland, Oregon
| | - Steven K Dobscha
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon; Mental Health and Clinical Neurosciences Division, Portland VA Medical Center, Portland, Oregon; Portland Center for the Study of Chronic, Comorbid Mental and Physical Disorders, Portland VA Medical Center, Portland, Oregon
| | - Benjamin J Morasco
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon; Mental Health and Clinical Neurosciences Division, Portland VA Medical Center, Portland, Oregon; Portland Center for the Study of Chronic, Comorbid Mental and Physical Disorders, Portland VA Medical Center, Portland, Oregon
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Crauwels HM, van Heeswijk RP, Vandevoorde A, Buelens A, Stevens M, Hoetelmans RM. The effect of rilpivirine on the pharmacokinetics of methadone in HIV-negative volunteers. J Clin Pharmacol 2013; 54:133-40. [DOI: 10.1002/jcph.222] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 10/31/2013] [Indexed: 11/10/2022]
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Chevillard L, Declèves X, Baud FJ, Risède P, Mégarbane B. Respiratory effects of diazepam/methadone combination in rats: a study based on concentration/effect relationships. Drug Alcohol Depend 2013; 131:298-307. [PMID: 23332448 DOI: 10.1016/j.drugalcdep.2012.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/12/2012] [Accepted: 12/18/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Methadone may cause respiratory depression and fatalities. Concomitant use of benzodiazepines in methadone-treated patients for chronic pain or as maintenance therapy for opiate abuse is common. However, the exact contribution of benzodiazepines to methadone-induced respiratory toxicity remains debatable. METHODS We investigated the respiratory effects of the combination diazepam (20mg/kg)/methadone (5mg/kg) in the rat, focusing on methadone concentration/effect relationships. Respiratory effects were studied using arterial blood gases and whole-body plethysmography. Plasma concentrations of both R- and S-methadone enantiomers were measured using high-performance liquid chiral chromatography coupled to mass spectrometry. To clarify mechanisms of diazepam/methadone interaction, methadone metabolism was investigated in vitro using rat liver microsomes. RESULTS Diazepam/methadone co-administration significantly increased methadone-related effects on inspiratory time (p<0.001) but did not significantly alter the other respiratory parameters when compared with methadone alone, despite significant increase in the area under the curve of plasma R-methadone concentrations measured during 240 min (p<0.05). Diazepam/methadone co-incubation with microsomes in vitro resulted in a significant inhibition of methadone metabolism (p<0.01), with 50%-inhibitory diazepam concentrations of 25.02 ± 0.18 μmol/L and 25.18 ± 0.23 μmol/L for R- and S-methadone, respectively. CONCLUSION We concluded that co-administration of high-doses of diazepam and methadone in rats is not responsible for additional respiratory depression in comparison to methadone alone, despite significant metabolic interaction between the drugs. In humans, although our experimental data may suggest the relative safety of benzodiazepine/methadone co-prescription, physicians should remain cautious as other underlying conditions may enhance this drug-drug interaction.
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Affiliation(s)
- Lucie Chevillard
- INSERM U705, CNRS UMR8206, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Neuropsychopharmacologie des addictions, Paris, France.
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Latuga NM, Wahler RG. Very-High-Dose Methadone With Minimal Toxicity and Inadequate Pain Control in a Hospice Patient With Cancer. J Pain Palliat Care Pharmacother 2013; 27:143-9. [DOI: 10.3109/15360288.2013.786011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Pilgrim JL, McDonough M, Drummer OH. A review of methadone deaths between 2001 and 2005 in Victoria, Australia. Forensic Sci Int 2013; 226:216-22. [DOI: 10.1016/j.forsciint.2013.01.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/13/2013] [Accepted: 01/23/2013] [Indexed: 12/01/2022]
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Gaertner J, Ruberg K, Schlesiger G, Frechen S, Voltz R. Drug interactions in palliative care--it's more than cytochrome P450. Palliat Med 2012; 26:813-25. [PMID: 21737479 DOI: 10.1177/0269216311412231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE This study aims to identify the combination of substances with high potential for drug interactions in a palliative care setting and to provide concise recommendations for physicians. METHODS We used a retrospective systematic chart analysis of 200 consecutive inpatients. The recently developed and internationally advocated classification system OpeRational ClAssification of Drug Interactions was applied using the national database of the Federal Union of German Associations of Pharmacists. Charts of patients with potential for severe DDIs were examined manually for clinical relevance. RESULTS In 151 patients (75%) a total of 631 potential drug interactions were identified. Opioids (exception: methadone), non-opioids (exception: non-steroidal anti-inflammatory drugs), benzodiazepines, proton-pump inhibitors, laxatives, co-analgesics (exception: carbamazepine) and butylscopolamine were generally safe. High potential for drug interactions included combinations of scopolamine, neuroleptics, metoclopramide, antihistamines, non-steroidal anti-inflammatory drugs, (levo-) methadone, amitriptyline, carbamazepine and diuretics. The manual analyses of records from eight patients with risk for severe drug interactions provided no indicator for clinical relevance in these specific patients. Drug interactions attributed to the cytochrome pathway played a minor role (exception: carbamazepine). CONCLUSION Most relevant drug interactions can be expected with: (i) drugs (inter-) acting via histamine, acetylcholine or dopamine receptors; and (ii) Non-steroidal anti-inflammatory drugs. Even in last hours of life the combination of substances (e.g. anticholinergics) may produce relevant drug interactions (e.g. delirium). PERSPECTIVE Data on the potential for drug-drug interactions in palliative case is extremely scarce, but drug interactions can be limited if a few facts are considered. A synopsis of the findings of these studies is presented as concise recommendation to minimize drug interactions.
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Affiliation(s)
- Jan Gaertner
- Department of Palliative Medicine, University Hospital Cologne, Germany.
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Abstract
Methadone is increasingly used in pain management and is a cornerstone in the treatment of opiate withdrawal. It is subject to highly variable clearance among patients. The complete metabolic disposition of methadone is likely to involve a number of enzymes, including specifically CYP2B6. Previous studies in vitro suggest that metabolism by aromatase may also contribute. Single-dose methadone pharmacokinetics (2 mg, intravenous) were studied in 15 healthy postmenopausal women in the presence and absence of a potent aromatase inhibitor, letrozole. A sequential design was used, involving a control period followed by treatment with letrozole (2.5 mg/d, 11 days), in which each subject served as her own control. On average, letrozole treatment reduced methadone systemic clearance by 22% (P = 0.001), increased methadone AUC by 23% (P = 0.007), and increased elimination half-life by 21% (P = 0.042). The plasma parent-to-metabolite ratio also increased (P = 0.009), and there was a linear relationship (R2 = 0.74) between change in this plasma ratio and change in methadone AUC0-∞. In contrast, there was no such association with change in apparent urinary methadone clearance. Letrozole did not change methadone distribution half-life or its volume of distribution. Overall, these data demonstrate a significant decrease in methadone clearance during coadministration of letrozole, consistent with decreased metabolism brought about by aromatase inhibition. An involvement of aromatase in the disposition of methadone may help explain the difficulty in methadone dosing and suggests a broader role for this catalyst of endogenous steroid metabolism in xenobiotic drug disposition.
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Domeque Valiente N, Prieto Andrés P, Lozano Ortiz R, Andrés Arribas I. Interacción farmacocinética entre metadona y metamizol: a propósito de 53 casos. Med Clin (Barc) 2012; 138:498-9. [DOI: 10.1016/j.medcli.2011.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 06/22/2011] [Accepted: 06/28/2011] [Indexed: 10/17/2022]
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Survey of methadone-drug interactions among patients of methadone maintenance treatment program in Taiwan. SUBSTANCE ABUSE TREATMENT PREVENTION AND POLICY 2012; 7:11. [PMID: 22429858 PMCID: PMC3373376 DOI: 10.1186/1747-597x-7-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 03/20/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Although methadone has been used for the maintenance treatment of opioid dependence for decades, it was not introduced in China or Taiwan until 2000s. Methadone-drug interactions (MDIs) have been shown to cause many adverse effects. However, such effects have not been scrutinized in the ethnic Chinese community. METHODS The study was performed in two major hospitals in southern Taiwan. A total of 178 non-HIV patients aged ≥ 20 years who had participated in the Methadone Maintenance Treatment Program (MMTP) ≥ 1 month were recruited. An MDI is defined as concurrent use of drug(s) with methadone that may result in an increase or decrease of effectiveness and/or adverse effect of methadone. To determine the prevalence and clinical characteristics of MDIs, credible data sources, including the National Health Insurance (NHI) database, face-to-face interviews, medical records, and methadone computer databases, were linked for analysis. Socio-demographic and clinical factors associated with MDIs and co-medications were also examined. RESULTS 128 (72%) MMTP patients took at least one medication. Clinically significant MDIs included withdrawal symptoms, which were found among MMTP patients co-administered with buprenorphine or tramadol; severe QTc prolongation effect, which might be associated with use of haloperidol or droperidol; and additive CNS and respiratory depression, which could result from use of methadone in combination with chlorpromazine or thioridazine. Past amphetamine use, co-infection with hepatitis C, and a longer retention in the MMTP were associated with increased odds of co-medication. Among patients with co-medication use, significant correlates of MDIs included the male gender and length of co-medication in the MMTP. CONCLUSIONS The results demonstrate clinical evidence of significant MDIs among MMTP patients. Clinicians should check the past medical history of MMTP clients carefully before prescribing medicines. Because combinations of methadone with other psychotropic or opioid medications can affect treatment outcomes or precipitate withdrawal symptoms, clinicians should be cautious when prescribing these medications to MMTP patients and monitor the therapeutic effects and adverse drug reactions. Although it is difficult to interconnect medical data from different sources for the sake of privacy protection, the incumbent agency should develop pharmacovigilant measures to prevent the MDIs from occurring. Physicians are also advised to check more carefully on the medication history of their MMTP patients.
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Lu WJ, Zhou W, Kreutz Y, Flockhart DA. Methadone adverse reaction presenting with large increase in plasma methadone binding: a case series. J Med Case Rep 2011; 5:513. [PMID: 21985665 PMCID: PMC3201932 DOI: 10.1186/1752-1947-5-513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 10/10/2011] [Indexed: 11/17/2022] Open
Abstract
Introduction The use of methadone as an analgesic is on the increase, but it is widely recognized that the goal of predictable and reproducible dosing is confounded by considerable variability in methadone pharmacokinetics, and unpredictable side effects that include sedation, respiratory depression and cardiac arrhythmias. The mechanisms underlying these unpredictable effects are frequently unclear. Here, to the best of our knowledge we present the first report of an association between accidental methadone overexposure and increased plasma protein binding, a new potential mechanism for drug interactions with methadone. Case presentation We describe here the cases of two patients who experienced markedly different responses to the same dose of methadone during co-administration of letrozole. Both patients were post-menopausal Caucasian women who were among healthy volunteers participating in a clinical trial. Under the trial protocol both patients received 6 mg of intravenous methadone before and then after taking letrozole for seven days. One woman (aged 59) experienced symptoms consistent with opiate overexposure after the second dose of methadone that were reversed by naloxone, while the other (aged 49) did not. To understand the etiology of this event, we measured methadone pharmacokinetics in both patients. In our affected patient only, a fourfold to eightfold increase in methadone plasma concentrations after letrozole treatment was observed. Detailed pharmacokinetic analysis indicated no change in metabolism or renal elimination in our patient, but the percentage of unbound methadone in the plasma decreased 3.7-fold. As a result, the volume of distribution of methadone decreased approximately fourfold. The increased plasma binding in our affected patient was consistent with observed increases in plasma protein concentrations. Conclusions The marked increase in the total plasma methadone concentration observed in our patient, and the enhanced pharmacodynamic effect, appear primarily due to a reduced volume of distribution. The extent of plasma methadone binding may help to explain the unpredictability of its pharmacokinetics. Changes in volume of distribution due to plasma binding may represent important causes of clinically meaningful drug interactions.
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Affiliation(s)
- Wenjie J Lu
- Division of Clinical Pharmacology, Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Chen CH, Wang SC, Tsou HH, Ho IK, Tian JN, Yu CJ, Hsiao CF, Chou SY, Lin YF, Fang KC, Huang CL, Su LW, Fang YC, Liu ML, Lin KM, Hsu YT, Liu SC, Chen ACH, Liu YL. Genetic polymorphisms in CYP3A4 are associated with withdrawal symptoms and adverse reactions in methadone maintenance patients. Pharmacogenomics 2011; 12:1397-406. [DOI: 10.2217/pgs.11.103] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: Methadone maintenance therapy is one of the standard treatments for heroin addiction. The isozyme CYP3A4 of the CYP system is one of the metabolic enzymes, as well as CYP2B6, responsible for the metabolism of methadone. The aim of the present study is to evaluate the potential use of genetic polymorphisms in CYP3A4 as biomarkers for the prediction of methadone treatment responses. Materials & methods: A total of 366 Han Chinese methadone maintenance treatment patients in Taiwan were recruited in this study. Main clinical assessments included the clinical opioid withdrawal scale (COWS), the treatment emergent symptom scale (TESS) and the plasma concentrations of methadone and its metabolites. Genetic associations of six SNPs in the CYP3A4 gene were calculated using a general linear model. Results: Genotypes and allele types of rs4646440 and rs2242480 were found to be significantly associated with the severity of withdrawal symptoms rated by COWS (p = 0.012, 0.0096, 0.017 and 0.012, respectively) as well as the side effects rated by TESS (p = 0.0089, 0.028, 0.0027 and 0.0085, respectively). The allele types associated with more severe withdrawal symptoms are also associated with more severe side effects and less betel nut (Areca catechu) use (p = 0.009 for rs4646440, p = 0.0063 for rs2242480). Further analyses on specific withdrawal symptoms in COWS showed that the genetic variants in rs4646440 are significantly associated with heart rate (allele type p = 0.0019). Conclusion: These results suggested that genetic variants in the CYP3A4 gene may be useful indicators for the severity of side effects and withdrawal symptoms for methadone treatment. Original submitted 2 May 2011; Revision submitted 8 July 2011
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Affiliation(s)
- Chia-Hui Chen
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan and Department of Psychiatry, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Sheng-Chang Wang
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Hsiao-Hui Tsou
- Division of Biostatistics & Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Ing-Kang Ho
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Jia-Ni Tian
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Cheng-Jou Yu
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan and Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chin-Fu Hsiao
- Division of Biostatistics & Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan and Division of Clinical Trial Statistics, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Sun-Yuan Chou
- Department of Psychiatry, Taoyuan Mental Hospital, Department of Health, Taoyuan County, Taiwan
| | - Yen-Feng Lin
- Departments of Psychiatry, En Chu Kong Hospital, New Taipei, Taiwan
| | - Kai-Chi Fang
- Department of Psychiatry, Far Eastern Memorial Hospital, New Taipei, Taiwan
| | - Chieh-Liang Huang
- College of Medicine, China Medical University, Taichung, Taiwan and Department of Psychiatry, & Center for Drug Abuse & Addiction, China Medical University Hospital, Taichung, Taiwan
| | - Lien-Wen Su
- Department of Psychiatry, Taipei City Hospital Song-De Branch, Taipei, Taiwan
| | - Yong-Chun Fang
- Department of Psychiatry, Taipei City Hospital Yang-Ming Branch, Taipei, Taiwan
| | - Ming-Lun Liu
- Department of Psychiatry, Wei Gong Memorial Hospital, Miaoli County, Taiwan
| | - Keh-Ming Lin
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Ya-Ting Hsu
- Division of Biostatistics & Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Shu Chih Liu
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Andrew CH Chen
- Department of Psychiatry, Columbia University, College of Physicians and Surgeons, NY, USA
| | - Yu-Li Liu
- Division of Mental Health & Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan and Graduate Institute of Drug Safety, China Medical University, Taichung, Taiwan and Department of Psychiatry, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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Cherny N. Is oral methadone better than placebo or other oral/transdermal opioids in the management of pain? Palliat Med 2011; 25:488-93. [PMID: 21708855 DOI: 10.1177/0269216310397687] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM To address the question: is oral methadone better than placebo, or other oral/transdermal opioids in the management of cancer pain? METHOD A literature search was performed to identify relevant studies. Search strategies included: (1) methadone (title) AND placebo (title or abstract) AND pain (title or abstract); (2) methadone (title) AND randomized (title or abstract) AND pain (title or abstract) AND cancer (title or abstract). Papers were reviewed for relevance to first-line opioid therapy. RESULTS No studies were identified comparing methadone to placebo for cancer pain. A single study compared methadone to placebo for neuropathic pain and demonstrated evidence of analgesic effect at a dose of 20 mg/day but not at a dose of 10 mg/day. Four studies compared oral methadone to either oral morphine, or oral morphine and transdermal fentanyl in a first-line setting: Gourlay 1986 (N = 18), Ventafridda 1986 (N =54), Bruera 2004 (N = 106) and Mercadante 2008 (N = 108). All studies demonstrated comparable, but not superior, analgesia with, overall, a comparable adverse effect profile. The duration of the study period for the three largest studies was 28 days. Two of these studies, Ventafridda 1986 and Mercadante 2008, indicated that, over time, the opioid escalation index was lower for methadone than for morphine. One study that used a 2:1 dose ratio between morphine and methadone was associated with a high attrition rate in the first week because of excessive sedation. This effect was not seen in the study that used a 4:1 morphine to methadone dose ratio with dose titration. CONCLUSION This limited data suggests that (1) methadone may be an equally effective candidate for first-line opioid therapy, (2) that it is possibly less expensive, (3) that there may be a propensity to sedation and dose accumulation unless there is close monitoring and conservative dose selection and (4) that it should be initiated with a calculated dose based on a morphine to methadone dose ratio of not less than 4:1.
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Affiliation(s)
- Nathan Cherny
- Department of Medical Oncology, Shaare Zedek Medical Center, Jerusalem, Israel.
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Matlock A, Allan N, Wills B, Kang C, Leikin JB. A continuing black hole? The FDA boxed warning: an appeal to improve its clinical utility. Clin Toxicol (Phila) 2011; 49:443-7. [PMID: 21591886 DOI: 10.3109/15563650.2011.564585] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The boxed warning is increasingly utilized by the Food and Drug Administration (FDA) as a clinical warning to prescribers of dangerous adverse drug reactions. As these warnings have expanded, we feel the utility and application of boxed warnings are becoming more nebulous. The use of drugs following issuance of a boxed warning has been variable. Droperidol sales decreased 10-fold in the year following the warning, yet there has been essentially no change in the methadone usage over a similar time period after its boxed warning. Including more information, such as estimation of incidence for the adverse drug reaction, would be more clinically useful to the prescriber. Reasonable standards using supplemental databases outside of the FDA (such as national poison center data) could be helpful in developing an integrated and balanced approach to boxed warnings.
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Affiliation(s)
- Aaron Matlock
- Department of Emergency Medicine, Madigan Army Medical Center, Tacoma, USA
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Dürsteler-MacFarland KM, Vogel M, Wiesbeck GA, Petitjean SA. There is no age limit for methadone: a retrospective cohort study. SUBSTANCE ABUSE TREATMENT PREVENTION AND POLICY 2011; 6:9. [PMID: 21592331 PMCID: PMC3118116 DOI: 10.1186/1747-597x-6-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 05/18/2011] [Indexed: 12/21/2022]
Abstract
Background Data from the US indicates that methadone-maintained populations are aging, with an increase of patients aged 50 or older. Data from European methadone populations is sparse. This retrospective cohort study sought to evaluate the age trends and related developments in the methadone population of Basel-City, Switzerland. Methods The study included methadone patients between April 1, 1995 and March 31, 2003. Anonymized data was taken from the methadone register of Basel-City. For analysis of age distributions, patient samples were split into four age categories from '20-29 years' to '50 years and over'. Cross-sectional comparisons were performed using patient samples of 1996 and 2003. Results Analysis showed a significant increase in older patients between 1996 and 2003 (p < 0.001). During that period, the percentage of patients aged 50 and over rose almost tenfold, while the proportion of patients aged under 30 dropped significantly from 52.8% to 12.3%. The average methadone dose (p < 0.001) and the 1-year retention rate (p < 0.001) also increased significantly. Conclusions Findings point to clear trends in aging of methadone patients in Basel-City which are comparable, although less pronounced, to developments among US methadone populations. Many unanswered questions on medical, psychosocial and health economic consequences remain as the needs of older patients have not yet been evaluated extensively. However, older methadone patients, just as any other patients, should be accorded treatment appropriate to their medical condition and needs. Particular attention should be paid to adequate solutions for persons in need of care.
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Affiliation(s)
- Kenneth M Dürsteler-MacFarland
- Division of Substance Use Disorders, Psychiatric Hospital of the University of Basel, Wilhelm Klein-Strasse 27, 4012 Basel, Switzerland.
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Comparative mortality among Department of Veterans Affairs patients prescribed methadone or long-acting morphine for chronic pain. Pain 2011; 152:1789-1795. [PMID: 21524850 DOI: 10.1016/j.pain.2011.03.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 03/08/2011] [Accepted: 03/21/2011] [Indexed: 11/21/2022]
Abstract
Data on comparative safety of opioid analgesics are limited, but some reports suggest disproportionate mortality risk associated with methadone. Our objective was to compare mortality rates among patients who received prescribed methadone or long-acting morphine for pain. This is a retrospective observational cohort drawn from Department of Veterans Affairs (VA) health care databases, January 1, 2000, to December 31, 2007. We included 28,554 patients who received methadone and 79,938 who received long-acting morphine from VA pharmacies. Compared with those who received long-acting morphine, patients who received methadone were younger, less likely to have some medical comorbidities, and more likely to have psychiatric and substance use disorders. Patients were stratified into quintiles according to propensity score; the probability of receiving methadone was conditional on demographic, clinical, and VA service area variables. Overall propensity-adjusted mortality was lower for methadone than for morphine. Hazard ratios varied across propensity score quintiles; the magnitude of the between-drug difference in mortality decreased as the propensity to receive methadone increased. Mortality was significantly lower for methadone in all but the last quintile, in which there was no between-drug difference in mortality (hazard ratio=0.92, 95% confidence interval=0.74, 1.16). Multiple sensitivity analyses found either no difference in mortality between methadone and long-acting morphine or lower mortality rates among patients who received methadone. In summary, we found no evidence of excess all-cause mortality among VA patients who received methadone compared with those who received long-acting morphine. Randomized trials and prospective observational research are needed to better understand the relative safety of long-acting opioids.
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Go F, Dykeman M, Santos J, Muxlow J. Supporting clients on methadone maintenance treatment: a systematic review of nurse's role. J Psychiatr Ment Health Nurs 2011; 18:17-27. [PMID: 21214680 DOI: 10.1111/j.1365-2850.2010.01628.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper discusses findings from a systematic review of literature pertaining to methadone maintenance in relation to the role of the nurse working in a general practice setting. Five electronic databases were searched for period of 2000-2008: Medline, CINAHL, Embase, PsycINFO and Cochrane Database of Systematic Reviews. Included studies were peer-reviewed literature articles that: (1) were dated no earlier than the year 2000; (2) represented a primary study (qualitative and quantitative), systematic review or meta-analysis; (3) focused on methadone maintenance for treatment of opiate dependence, not for pain; and (4) were published in English. In this review, three broad themes emerged as being significant to the role of the nurse in relation to methadone maintenance treatment (MMT) programming. These themes included: (1) identifying the client's personal characteristics; (2) having knowledge about methadone; and (3) supporting clients in MMT programmes. In conclusion, it is important to address the needs of health professionals working with clients on MMT, in order for them to provide the necessary care for this patient population. In particular, nurses need to gain knowledge about MMT to assist them in carrying out their nursing role competently when caring for this vulnerable population.
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Affiliation(s)
- Frederick Go
- Faculty of Nursing, University of New Brunswick, Fredericton, NB, and Clinical Nurse Specialist, First Nations and Inuit Health, Atlantic Region, Halifax, NS, Canada.
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Deaths involving contraindicated and inappropriate combinations of serotonergic drugs. Int J Legal Med 2010; 125:803-15. [PMID: 21120513 DOI: 10.1007/s00414-010-0536-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/18/2010] [Indexed: 12/23/2022]
Abstract
In the Australian state of Victoria, all fatalities that were recorded from 2002 through to 2008 involving the use of certain serotonin active drugs (tramadol, venlafaxine, fluoxetine, sertraline, citalopram and paroxetine), were reviewed to assess the incidence of contraindicated or ill advised drug combinations. More than 1,000 were identified of which 326 cases formed the basis of this study. These cases involved contraindicated or inappropriate drug combinations that can lead to adverse drug reactions (ADRs) and subsequent fatal toxicity. Of these, 46% were drug-related, 35% were a result of natural disease and 13% were classified as external injury cases. The remaining cases were those where the cause of death (COD) was unascertained. Tramadol was the most common drug, usually detected alongside a serotonergic antidepressant (in 20% of cases). Twenty-five (8%) cases involved contraindicated drug combinations while the remainder (301 cases, 92%) involved drug combinations that are associated with adverse interactions ranging from minor to major severity. Of these 326 cases, the Coroner determined 166 cases (51%) to be acts of intentional self-harm or drug misuse, with the remainder unascertained or attributed to natural disease. Very few post-mortem reports and Coroners' findings made mention of possible ADRs when such combinations were actually present. The majority of cases comprising contraindicated drug combinations involved the combined use of five drugs (24%) at the time of death. A combination of three to five drugs was most common in cases involving inadvisable drug combinations. Combined drug toxicity was the most common COD, with heart disease the most common co-morbidity.
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Jiao M, Greanya ED, Haque M, Yoshida EM, Soos JG. Methadone maintenance therapy in liver transplantation. Prog Transplant 2010. [PMID: 20929104 DOI: 10.7182/prtr.20.3.r8n4k17212158k62] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cirrhosis due to chronic infection with hepatitis C virus remains by far the most common reason for liver transplantation in North America. Currently, parenteral use of street drugs is the most common means of acquiring hepatitis C. Methadone maintenance therapy is an accepted form of treatment for chronic opiate (eg, heroin) addiction and, not surprisingly, a significant proportion of methadone-treated patients have chronic hepatitis C. The feasibility of liver transplant candidacy in hepatitis patients who require methadone maintenance therapy is controversial, and some transplant centers require patients to withdraw from such therapy in order for the transplant process to move forward. Thus stable patients with end-stage cirrhosis who are receiving methadone maintenance are left in a most difficult situation: discontinue methadone and accept the side effects of withdrawal with the risk of recidivism to use of street opiates, an absolute contraindication for transplantation, or continue methadone therapy and risk exclusion from the transplant process. The issue of methadone replacement therapy in end-stage cirrhosis and the posttransplant literature on the subject are explored in this paper.
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Affiliation(s)
- Modi Jiao
- University of Toronto Scarborough, Toronto, Ontario
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Review: Pharmacogenetic aspects of the effect of cytochrome P450 polymorphisms on serotonergic drug metabolism, response, interactions, and adverse effects. Forensic Sci Med Pathol 2010; 7:162-84. [PMID: 21052868 DOI: 10.1007/s12024-010-9188-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2010] [Indexed: 12/26/2022]
Abstract
The field of pharmacogenetics contains a wealth of potential for the enhancement of clinical practice by providing a more effective match between patient and drug, consequently reducing the probability of an adverse drug reaction. Although a relatively novel concept in the forensic context, pharmacogenetics has the capability to assist in the interpretation of drug related deaths, particularly in unintentional drug poisonings where the cause of death remains unclear. However, the complex pharmacology of the drugs when subjected to genetic variations in metabolism makes interpretation of the expected response and adverse events difficult. Many possess multiple metabolic pathways, narrow therapeutic indices and active metabolites or enantiomers which may be eliminated via different pathways to the parent drug. A number of these drugs, which are metabolised primarily by the CYP450 system, are also associated with serotonin syndrome, or serotonin toxicity, especially when used concomitantly with other serotonin active drugs which rely on the same metabolic pathways for drug elimination. A comprehensive understanding of polymorphic drug metabolism and its expected outcomes is therefore essential when interpreting the involvement of drugs in adverse reactions. This review examines the genetically variable CYP450-mediated metabolism of a number of serotonin-active drugs that are often implicated in cases of serotonin toxicity, to assess the impact of pharmacogenetics on drug metabolism, response, interactions and adverse effects.
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