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Mohamad N, Abdul Jalal MI, Hassan A, Abdulkarim Ibrahim M, Salehuddin R, Abu Bakar NH. Pattern of QTc prolongation in Methadone Maintenance Therapy (MMT) subjects receiving different methadone dosages: A prospective cohort study. Pak J Med Sci 2013; 29:1132-6. [PMID: 24353706 PMCID: PMC3858916 DOI: 10.12669/pjms.295.3395] [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] [Received: 01/19/2013] [Revised: 02/06/2013] [Accepted: 07/12/2013] [Indexed: 11/18/2022] Open
Abstract
Objectives: This study aimed to compare the QTc interval between low and high dose methadone groups and evaluate the pattern of QTc variation. Methods: This is a prospective cohort study conducted from December 2010 till August 2011 at Malaysian University of Science’s Hospital. Forty six subjects, grouped in high dose (>80mg) and low dose (<80mg) oral methadone, were followed-up at 4-weekly for QTc measurements. Relevant demographic and biochemical profiles were taken at intervals with concurrent QTc measurements. Results: No significant QTc differences between methadone dosage groups were found at Week 0 (434ms vs 444ms, p = 0.166) and week 8 (446.5ms vs 459ms, p = 0.076), but not at week 4(435ms vs 450ms, p = 0.029). However, there were significant associations between the groups with QTc prolongation at week 0 and 4 (OR 4.29(95% CI 1.01, 18.72) p=0.044 and OR 5.18 (95% CI 1.34, 20.06) p =0.013, respectively) but not at week 8 (OR 2.44 (95% CI 0.74, 8.01) p=0.139). On multivariate analysis, dose group was the sole significant factor for QTc prolongation for week 0 and 4 (p values 0.047 and 0.017, respectively), but not at week 8. Conclusion: High-dose methadone group is more likely to develop prolonged QTc than low-dose group. However, such effects were inconsistent and occurred even during chronic methadone therapy, mandating judicious QTc and serum methadone monitoring.
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Affiliation(s)
- Nasir Mohamad
- Nasir Mohamad, MD, MMed, Department of Emergency Medicine, School of Medical Sciences, USM, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Muhammad Irfan Abdul Jalal
- Muhammad Irfan Abdul Jalal, MBChB, MSc (Medical Statistics), INFORMM, USM, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Azlie Hassan
- Azlie Hassan, MD, MMed, Department of Emergency Medicine, School of Medical Sciences, USM, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Muslih Abdulkarim Ibrahim
- Muslih Abdulkarim Ibrahim, B.Pharm, Msc (Pharmacy), INFORMM, USM, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Roslanuddin Salehuddin
- Roslanuddin Salehuddin, MD, MMed, Department of Emergency Medicine, School of Medical Sciences, USM, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Nor Hidayah Abu Bakar
- Nor Hidayah Abu Bakar, MD, MMed, Department of Pathology, Hospital Sultanah Zainab 2, 15860, Kota Bharu, Kelantan, Malaysia
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Jantos R, Skopp G. Postmortem blood and tissue concentrations of R- and S-enantiomers of methadone and its metabolite EDDP. Forensic Sci Int 2013; 226:254-60. [DOI: 10.1016/j.forsciint.2013.01.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 01/22/2013] [Accepted: 01/26/2013] [Indexed: 11/25/2022]
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Martin JA, Campbell A, Killip T, Kotz M, Krantz MJ, Kreek MJ, McCarroll BA, Mehta D, Payte JT, Stimmel B, Taylor T, Haigney MCP, Wilford BB. QT interval screening in methadone maintenance treatment: report of a SAMHSA expert panel. J Addict Dis 2011; 30:283-306. [PMID: 22026519 PMCID: PMC4078896 DOI: 10.1080/10550887.2011.610710] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In an effort to enhance patient safety in opioid treatment programs, the Substance Abuse and Mental Health Saervices Administration convened a multi-disciplinary Expert Panel on the Cardiac Effects of Methadone. Panel members (Appendix A) reviewed the literature, regulatory actions, professional guidances, and opioid treatment program experiences regarding adverse cardiac events associated with methadone. The Panel concluded that, to the extent possible, every opioid treatment program should have a universal Cardiac Risk Management Plan (incorporating clinical assessment, electrocardiogram assessment, risk stratification, and prevention of drug interactions) for all patients and should strongly consider patient-specific risk minimization strategies (such as careful patient monitoring, obtaining electrocardiograms as indicated by a particular patient's risk profile, and adjusting the methadone dose as needed) for patients with identified risk factors for adverse cardiac events. The Panel also suggested specific modifications to informed consent documents, patient education, staff education, and methadone protocols.
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Doxepin and nordoxepin concentrations in body fluids and tissues in doxepin associated deaths. Forensic Sci Int 2009; 190:74-9. [DOI: 10.1016/j.forsciint.2009.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/17/2009] [Accepted: 05/20/2009] [Indexed: 11/18/2022]
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Guay DR. Cardiotoxicity of Oral Methadone as an Analgesic–-Recommendations for Safe Use. ACTA ACUST UNITED AC 2009. [DOI: 10.4137/cmt.s3041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Once used only as third-line therapy in the management of chronic pain states, methadone is now being used as first- and second-line therapy. Most risks and the stigma associated with methadone use have been known for years. Only over the past decade or so have the unique pharmacokinetic-pharmacodynamic properties and methods for conversion from other opioids to methadone been established. Pertinent English-language literature was obtained from MEDLINE/PUBMED and EMBASE searches (1966-June 2009). This paper provides an overview of the cardiotoxicity of oral methadone, with an emphasis on its use as an analgesic. Cardiotoxicity during its use in the maintenance of opioid addiction has also been reviewed due to the wealth of epidemiologic, risk factor, and correlative analytic data contained therein. A series of recommendations are provided to improve the cardiac safety profile of oral methadone used for analgesia. In addition, there is a discussion of settings and patient types which may impact upon these recommendations.
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Affiliation(s)
- David R.P. Guay
- College of Pharmacy, University of Minnesota and HealthPartners Geriatrics, HealthPartners Inc., Minneapolis, Minnesota, USA
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Stringer J, Welsh C, Tommasello A. Methadone-associated Q-T interval prolongation and torsades de pointes. Am J Health Syst Pharm 2009; 66:825-33. [PMID: 19386945 DOI: 10.2146/ajhp070392] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE The association of methadone with Q-T interval prolongation and torsades de pointes (TdP) is reviewed, and recommendations for preventing Q-T interval prolongation in methadone users are provided. SUMMARY Abnormalities in voltage-gated potassium channels have been shown to lead to prolonged action potentials that are expressed as long Q-T intervals, and methadone has been found to interact with the voltage-gated potassium channels of the myocardium. While cardiac arrhythmias in methadone users have been reported for several decades, specific reports of methadone-associated Q-T interval prolongation and TdP did not appear in the literature until the early part of the 21st century. Because not every patient experiences Q-T interval prolongation with methadone, recent research has elucidated risk factors that predispose patients to this adverse effect, including female sex, hypokalemia, high-dose methadone, drug interactions, underlying cardiac conditions, unrecognized congenital long Q-T interval syndrome, and predisposing DNA polymorphisms. Given the high mortality rates seen in untreated illicit opioid users and the clear efficacy of methadone in treating opioid addiction, the risk of using methadone, even in a patient with other risk factors for Q-T interval prolongation, may outweigh the alternative of no pharmacologic treatment. A baseline electrocardiogram (ECG), personal and family history of syncope, and a complete medication history should be obtained before a patient begins treatment with methadone. Given the apparent synergistic effects of parenteral methadone and chlorobutanol, oral methadone should be used whenever possible. CONCLUSION Q-T interval prolongation and TdP associated with the use of methadone are potentially fatal adverse effects. A thorough patient history and ECG monitoring are essential for patients treated with this agent, and alterations in treatment options may be necessary.
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Affiliation(s)
- John Stringer
- Pharmacy, Saint Barnabas Behavioral Health Center, Toms River, NJ 08754, USA.
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Cruciani RA. Methadone: to ECG or not to ECG...That is still the question. J Pain Symptom Manage 2008; 36:545-52. [PMID: 18440771 DOI: 10.1016/j.jpainsymman.2007.11.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 11/19/2007] [Accepted: 11/23/2007] [Indexed: 01/18/2023]
Abstract
There is significant controversy about the potential deleterious effect of methadone on cardiac conduction. Although several reports suggest that patients receiving methadone are at increased risk for QTc prolongation and torsade de pointes, a potentially fatal arrhythmia, others have not replicated these findings. Hence, it is not surprising that there is no consensus on when to perform an electrocardiogram, a simple test to assess the QTc interval, during methadone therapy. Most of the uncertainty is generated by the lack of large controlled studies. This review presents the current data on this issue in an effort to help in the decision-making process until more conclusive data become available.
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Affiliation(s)
- Ricardo A Cruciani
- Research Division, Department of Pain Medicine and Palliative Care, Beth Israel Medical Center, New York 10003, USA.
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Ehret GB, Desmeules JA, Broers B. Methadone-associated long QT syndrome: improving pharmacotherapy for dependence on illegal opioids and lessons learned for pharmacology. Expert Opin Drug Saf 2007; 6:289-303. [PMID: 17480178 DOI: 10.1517/14740338.6.3.289] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Methadone is used as the pharmacologic mainstay for substitution for illegal opiates and as analgesic for chronic or cancer-related pain. Given the benefits of methadone substitution for illicit opioids, the finding of an association between methadone and prolongation of cardiac depolarization (QT prolongation) and torsades de pointes is of great concern. QT prolongation can occur with many drugs and is a potentially lethal adverse drug reaction, necessitating risk monitoring and therapeutic alternatives in some patients. Recent studies suggest that QT prolongation with methadone is context dependent: occurrence is more frequent with high doses of methadone, concomitant administration of CYP3A4 inhibitors, hypokalemia, hepatic failure, administration of other QT prolonging drugs and pre-existing heart disease. The valued benefit of methadone substitution therapy on the one hand and the increased cardiovascular risk in particular situations on the other illustrate the difficulties in dealing with drug-induced QT prolongation in general.
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Affiliation(s)
- Georg B Ehret
- Johns Hopkins University School of Medicine, McKusick Nathans Institute of Genetic Medicine, Baltimore, MD 21205, USA.
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Duncan R, McPate M, Ridley J, Gao Z, James A, Leishman D, Leaney J, Witchel H, Hancox J. Inhibition of the HERG potassium channel by the tricyclic antidepressant doxepin. Biochem Pharmacol 2007; 74:425-37. [PMID: 17560554 PMCID: PMC1920586 DOI: 10.1016/j.bcp.2007.04.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2007] [Revised: 04/25/2007] [Accepted: 04/27/2007] [Indexed: 11/25/2022]
Abstract
HERG (human ether-à-go-go-related gene) encodes channels responsible for the cardiac rapid delayed rectifier potassium current, IKr. This study investigated the effects on HERG channels of doxepin, a tricyclic antidepressant linked to QT interval prolongation and cardiac arrhythmia. Whole-cell patch-clamp recordings were made at 37 °C of recombinant HERG channel current (IHERG), and of native IKr ‘tails’ from rabbit ventricular myocytes. Doxepin inhibited IHERG with an IC50 value of 6.5 ± 1.4 μM and native IKr with an IC50 of 4.4 ± 0.6 μM. The inhibitory effect on IHERG developed rapidly upon membrane depolarization, but with no significant dependence on voltage and with little alteration to the voltage-dependent kinetics of IHERG. Neither the S631A nor N588K inactivation-attenuating mutations (of residues located in the channel pore and external S5-Pore linker, respectively) significantly reduced the potency of inhibition. The S6 point mutation Y652A increased the IC50 for IHERG blockade by ∼4.2-fold; the F656A mutant also attenuated doxepin's action at some concentrations. HERG channel blockade is likely to underpin reported cases of QT interval prolongation with doxepin. Notably, this study also establishes doxepin as an effective inhibitor of mutant (N588K) HERG channels responsible for variant 1 of the short QT syndrome.
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Affiliation(s)
- R.S. Duncan
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
| | - M.J. McPate
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
| | - J.M. Ridley
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
| | - Z. Gao
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
| | - A.F. James
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
| | - D.J. Leishman
- Pfizer Global Research & Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, UK
- Lilly Research Laboratories, Greenfield Laboratories, PO Box 708, Greenfield IN, 46140, USA
| | - J.L. Leaney
- Pfizer Global Research & Development, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, UK
| | - H.J. Witchel
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
- Corresponding authors. Tel.: +117 928 9028; fax: +117 928 8923.
| | - J.C. Hancox
- Department of Physiology and Cardiovascular Research Laboratories, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
- Corresponding authors. Tel.: +117 928 9028; fax: +117 928 8923.
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Justo D, Gal-Oz A, Paran Y, Goldin Y, Zeltser D. Methadone-associated Torsades de Pointes (polymorphic ventricular tachycardia) in opioid-dependent patients. Addiction 2006; 101:1333-8. [PMID: 16911733 DOI: 10.1111/j.1360-0443.2006.01512.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS We reviewed all the publications concerning methadone-associated Torsades de Pointes (TdP) (polymorphic ventricular tachycardia) in opioid-dependent patients in order to characterize the clinical circumstances leading to this serious complication. METHODS Our literature search yielded 14 reports on 40 patients with methadone-associated TdP. We gathered and recorded the risk factors for TdP mentioned in those reports, among other clinical aspects. RESULTS The most prevalent risk factors for TdP were high-dose methadone (n = 39, 97.5%) and concomitant use of agents that increase serum methadone levels or trigger TdP (n = 22, 55%). HIV infection (n = 16), hypokalaemia (n = 14), female sex (n = 13), liver cirrhosis or renal failure (n = 11) and heart disease (n = 9) were also described. All the patients had at least one and 34 (85%) had two or more risk factors for TdP during methadone treatment. CONCLUSIONS We wish to raise the level of awareness of risk factors for TdP among physicians in heroin-treatment clinics who frequently prescribe methadone.
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Affiliation(s)
- Dan Justo
- Department of Internal Medicine D, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, 6 Weitzman Street, Tel Aviv 64239, Israel.
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Current awareness: Pharmacoepidemiology and drug safety. Pharmacoepidemiol Drug Saf 2006. [DOI: 10.1002/pds.1177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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