QTc interval screening for cardiac risk in methadone treatment of opioid dependence

[Recreative drug use and cardiovascular disease]

Widely spread, and continuously increasing, recreational drug use in general population has been associated with cardiovascular events, as illustrated by clinical studies and supported by a pathophysiological rationale. Understanding the cardiovascular effects of drugs, screening, and secondary prevention are crucial components in the management of those patients in cardiology.

Influence of CYP2B6 Genotype on Methadone Dosage in Patients from the Methadone Maintenance Treatment (MMT) Program in Pereira, Colombia

Methadone treatment reduces the use of heroin and withdrawal symptoms; however, methadone is an expensive medication with a narrow safety margin. We compared the retention rates, persistence of heroin use, and quality of life of a group of patients undergoing conventional Methadone Maintenance Treatment (MMT) with a group for whom the CYP2B6 516G>T polymorphism was used in addition to the MMT to calculate the required methadone dose. Over 12 weeks, the retention rate, heroin usage, and quality of life of patients under conventional treatment (n = 34) were compared with those of patients for whom we used genetic markers to calculate methadone dosage (n = 38). At the end of the study, 26.4% of patients abandoned the program, and neither demographic nor clinical variables were associated with treatment adherence. Of the remaining patients, 16% of the control group and 8% of patients in the pharmacogenetic group reported heroin use, while both groups showed a 64% reduction in the use of cocaine/crack (no significant differences between the groups were found). Starting in the second week, the methadone dosage was lower among the patients for whom methadone was prescribed based on genotype. Although there were six individuals in the control group and three in the pharmacogenetic group with QTc intervals > 450 ms (a threshold that is considered dangerous), we did not find a relationship between the QTc interval and methadone dosage. There were no differences in the perception of quality of life between the two groups. The results of this pilot study suggest that concerning methadone therapy, the CYP2B6 genotype contributes to reduced effective doses and treatment costs.

Effect of methadone on QTc in infants

OBJECTIVE

Methadone has been associated with prolongation of the QTc interval (QTc) on electrocardiogram (ECG). In infants, the effects of methadone on the QTc are not well described. Our study's objective is to evaluate the QTc in infants being treated with methadone.

METHODS

We conducted a retrospective study in infants receiving methadone. We collected demographic data, methadone dose, and QTc. A blinded-to-disease-state pediatric electrophysiologist determined the QTc. Baseline ECG was defined as an ECG obtained while not on methadone therapy, and QTc on baseline ECG was compared with treatment QTc. A significant change was defined as any absolute QTc greater than 500 or a QTc greater than 460 with an increase from baseline of greater than 40 ms.

RESULTS

A total of 44 infants comprised the study population. The mean gestational age was 32.3 ± 5.51 weeks. The median age of initiation was 66 days. The median dose was 0.52 mg/kg/day in oral methadone equivalents. Nine patients were on high dose methadone (>1 mg/kg/day in oral methadone equivalents). The mean baseline QTc was 421 ± 27 and the mean change on methadone was -2 ms. No patient had a QTc greater than 500 on methadone. One patient had a QTc of 467 and 46 ms change from baseline, with no clinically significant impact.

CONCLUSION

In our study population, methadone did not significantly prolong the QTc. Further prospective study is warranted to determine the utility and frequency of ECGs in infants receiving methadone.

Treatment of opioid dependence with buprenorphine: current update

Opioid maintenance treatment is the first-line approach in opioid dependence. Both the full opioid agonist methadone (MET) and the partial agonist buprenorphine (BUP) are licensed for the treatment of opioid dependence. BUP differs significantly from MET in its pharmacology, side effects, and safety issues. For example, the risk of respiratory depression is lower than with MET. The risk of diversion and injection of BUP have been reduced by also making it available as a tablet containing the opioid antagonist naloxone. This review summarizes the clinical effects of BUP and examines possible factors that can support decisions regarding the use of BUP or MET in opioid-dependent people.

Methadone and the QTc Interval: Paucity of Clinically Significant Factors in a Retrospective Cohort

OBJECTIVE

Methadone is associated with prolongation of the electrocardiographic QTc interval. QTc prolongation may be linked to cardiac dysrhythmia and sudden cardiac death. The rate of these events is unknown in methadone-maintained patients.

METHODS

This retrospective cohort study of 749 patients with opioid use disorder receiving methadone maintenance therapy through a single safety-net hospital, queried the electronic health record for electrocardiogram results, demographics, methadone dose, and diagnostic codes consistent with cardiac conduction disorder (International Classification of Disease, Ninth Revision [ICD-9] 426) and cardiac dysrhythmia (ICD-9 427). Factors associated with QTc interval were explored; Cox proportional-hazards regression models were used to analyze time to an event that may predispose to sudden cardiac death.

RESULTS

One hundred thirty-four patients had an electrocardiogram while on methadone, 404 while off methadone, and 211 both while on and off methadone. Mean QTc interval while on methadone (436 ms, SD 36) was significantly greater than while off methadone (423 ms, SD 33). Age and methadone dose were weakly associated with increased QTc interval (P < 0.01 and P < 0.0005, respectively, adjusted R = 0.05). There were 44 ICD-9 426 and 427 events over 7064 patient-years (6.3 events/1000 patient-yrs). Having a QTc greater than sex-specific cut-off values was significantly associated with time to event (hazard ratio 3.32, 95% confidence interval 1.25-8.81), but being on methadone was not.

CONCLUSIONS

Methadone is associated with QTc prolongation in a nonclinically significant dose-related manner. Cardiac events were rare and the sudden cardiac death rate was below that of the general population. Current recommendations for cardiac risk assessment in methadone-maintained patients should be reconsidered.

2017 HIVMA of IDSA Clinical Practice Guideline for the Management of Chronic Pain in Patients Living With HIV

Pain has always been an important part of human immunodeficiency virus (HIV) disease and its experience for patients. In this guideline, we review the types of chronic pain commonly seen among persons living with HIV (PLWH) and review the limited evidence base for treatment of chronic noncancer pain in this population. We also review the management of chronic pain in special populations of PLWH, including persons with substance use and mental health disorders. Finally, a general review of possible pharmacokinetic interactions is included to assist the HIV clinician in the treatment of chronic pain in this population.It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The Infectious Diseases Society of American considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Presence or Absence of QTc Prolongation in Buprenorphine-Naloxone Among Youth With Opioid Dependence

OBJECTIVES

The aim of the study was to evaluate buprenorphine-naloxone effects on the QTc in youth with opioid dependence. Buprenorphine is a partial agonist that is an effective treatment for opioid dependence. Compared with methadone, it has a lower risk of QTc prolongation in adults, but is less studied in the youth. It may also reduce the risk of torsades de pointes (TdP)--an uncommon variant of polymorphic ventricular tachycardia--that can result in syncope, ventricular fibrillation, and sudden death.

METHODS

Secondary analysis of the electrocardiogram data from 95 individuals who participated in a multisite trial for youth with opioid dependence. The participants were randomized to a 2-week (DETOX) or a 12-week course of buprenorphine-naloxone (BUP). At baseline, 12-lead electrocardiograms were done at weeks 4 and 12, and QTc intervals were hand-measured and calculated using Bazett formula. Increases above 60 milliseconds were considered clinically significant, and readings above 450 milliseconds (in men) and 470 milliseconds (in women) indicated a prolonged QTc.

RESULTS

Mean QTc intervals were higher for BUP than for DETOX participants at baseline, week 4, and week 12 (P = 0.045), and women had longer mean QTc intervals than men (P < 0.0005). Variations in the QTc intervals were observed in some; however, none were above 500 milliseconds--the level at which risk for TdP becomes more significant.

CONCLUSIONS

In this randomized trial, the mean QTc at baseline, before randomization, was higher in BUP than in DETOX patients. Minimal changes in the QTc were seen at 4 and 12 weeks in a few patients in both groups. There was no evidence that buprenorphine-naloxone alone increased the QTc to a level that increased the risk for TdP.

Risk-factors for methadone-specific deaths in Scotland's methadone-prescription clients between 2009 and 2013

AIM

To quantify gender, age-group and quantity of methadone prescribed as risk factors for drugs-related deaths (DRDs), and for methadone-specific DRDs, in Scotland's methadone-prescription clients.

DESIGN

Linkage to death-records for Scotland's methadone-clients with one or more Community Health Index (CHI)-identified methadone prescriptions during July 2009 to June 2013.

SETTING

Scotland's Prescribing Information System and National Records of Scotland.

MEASUREMENTS

Covariates defined at first CHI-identified methadone prescription, and person-years at-risk (pys) thereafter until the earlier of death-date or 31 December 2013. Methadone-specific DRDs were defined as: methadone implicated but neither heroin nor buprenorphine. Hazard ratios (HRs) were assessed using proportional hazards regression.

FINDINGS

Scotland's CHI-identified methadone-prescription cohort comprised 33,128 clients, 121,254 pys, 1,171 non-DRDs and 760 DRDs (6.3 per 1,000 pys), of which 362 were methadone-specific. Irrespective of gender, methadone-specific DRD-rate, per 1,000 pys, was higher in the 35+ age-group (4.2; 95% CI: 3.6-4.7) than for younger clients (1.9; 95% CI: 1.5-2.2). For methadone-specific DRDs, age-related HRs (e.g., 2.9 at 45+ years; 95% CI: 2.1-3.9) were steeper than for all DRDs (1.9; 95% CI: 1.5-2.4); there was no hazard-reduction for females; no gender by age-group interaction; and, unlike for all DRDs, the highest quintile for quantity of prescribed methadone at cohort-entry (>1960mg) was associated with increased HR (1.8; 95% CI: 1.3-2.5).

CONCLUSION

Higher methadone-specific DRD rates in older clients, irrespective of gender, call for better understanding of methadone's pharmaco-dynamics in older, opioid-dependent clients, many with progressive physical or mental ill-health.

Sustained release oral morphine as an alternative to methadone for the treatment of opioid-use disorder post Torsades de Pointes cardiac arrest

In most settings, approved medications for the treatment of opioid-use disorder include methadone and buprenorphine/naloxone, and in some settings, naltrexone. We present a case in which methadone administration was associated with an in-hospital episode of Torsades de Pointes in a patient who was subsequently maintained on sustained release oral morphine (SROM) for treatment of his opioid-use disorder. This transition was made in the context of long-term compliance to methadone maintenance, and with a previous adverse reaction to buprenorphine/naloxone precluding its use. The change to SROM, supported by emerging evidence, resulted in a reduction in the patient's measured QTc interval, prevention of further arrhythmias and continued abstinence from illicit opioid-use. In this context, we believe careful consideration should be given to the use of SROM.

QTc Prolongation in Veterans With Heroin Dependence on Methadone Maintenance Treatment

Background:

QTc prolongation and Torsade de Ppointes have been reported in patients on methadone maintenance.

Objectives:

In this study, QTc was compared before and after the veteran (n = 49) was on a stable dosage of methadone for 8.72 ± 4.50 years to treat heroin dependence. Risk factors were correlated with the QTc once the veteran was on a stable dose of methadone. Differences in the clinical risk factors in subgroups of veterans with below and above mean QTc change was compared.

Patients and Methods:

ECG data was obtained from a 12-lead electrocardiogram (pre-methadone and on methadone) on 49 veterans. Data and risk factors were retrospectively collected from the medical records.

Results:

The mean QTc at baseline (pre-methadone) was 426 ± 34 msec and after being on methadone for an average of 8.72 ± 4.50 years was significantly higher at 450 ± 35 msec. No significant relationships were found between QTc prolongation and risk factors except for calcium. The methadone dosage was significantly higher in veterans with a QTc change above the mean change of ≥ 24 msec (88.48 ± 27.20 mg v.s 68.96 ± 19.84 mg). None of the veterans experienced cardiac arrhythmias.

Conclusions:

The low complexity of medical co-morbidities may explain the lack of a significant correlation between any risk factor with the QTc except calcium and methadone dosage. The absence of TdP may be explained by the low prevalence of QTc values > 500 msec as well as the retrospective design of the study. During long-term methadone treatment, there was a slight increase in the QTc interval but we did not find evidence of increased cardiac toxicity as a reason for treatment termination.