Effects of Methadone on QT-Interval Dispersion

Opioid Use and the Risk of Ventricular Arrhythmias: A Systematic Review and Meta-Analysis

BACKGROUND

The association between opioid use and the risk of ventricular arrhythmias (VA) is poorly understood.

AIMS

The objective of this study was to synthesize the evidence on the risk of VA associated with opioid use.

MATERIALS & METHODS

We systematically searched the Cochrane Library, Embase, MEDLINE, and CINAHL databases in July 2022. Risk of bias was assessed using the Cochrane risk for bias tool for randomized controlled trials (RCTs) and ROBINS-I for observational studies. Certainty of evidence was assessed using GRADE.

RESULTS

We included 15 studies (12 observational, 2 post hoc analyses of RCTs, 1 RCT). Most studies focused on opioid use for maintenance therapy (n = 9), comparing methadone to buprenorphine (n = 13), and reported QTc prolongation (n = 13). Six observational studies had a critical risk of bias, and one RCT was at high risk of bias. Two studies could not be included in the meta-analysis as they reported a different outcome and studied an opioid antagonist. Meta-analysis of 13 studies indicated that the use of methadone was associated with an increased risk of VA compared to the use of buprenorphine, morphine, placebo, or levacetylmethadol (risk ratio [RR], 2.39; 95% CI, 1.31-4.35; I2 = 60%). The pooled estimate varied greatly between observational studies (RR, 2.12; 95% CI, 1.15-3.91; I2 = 62%) and RCTs (RR, 14.09; 95% CI, 1.52-130.61; I2 = 0%), but both indicated an increased risk.

CONCLUSION

In this systematic review and meta-analysis, we found that methadone use is associated with more than twice the risk of VA compared to comparators. However, our findings should be interpreted cautiously given the limited quality of the available evidence.

Long-acting opioids and cardiovascular diseases: Help or hindrance!

Opioids are widely being used for chronic pain management, cough and diarrhea suppressants, anesthetic agents, and opioid de-addiction therapy. Opioid receptors, present in the central nervous system and peripheral tissues, are documented to regulate several cardiac functions through different signaling pathways. Long-acting opioids (LAO) have been successfully evaluated for their beneficial effects in various cardiovascular diseases viz. myocardial infarction, ischemic reperfusion injuries, atherosclerosis etc. However, on the other hand, several research studies pointed towards the harmful effects of LAOs which are mainly associated with QTc prolongation, torsade de pointes, ventricular arrhythmias, and cardiac arrest. This review shall familiarize readers with the benefits as well as the harmful effects of long-acting opioids in cardiovascular diseases. We have also provided an overview of cardiac opioid receptors, endogenous cardiac opioid peptides, and regulation of cardiovascular functions by central and cardiac opioid receptors.

Management of opioid use disorder and associated conditions among hospitalized adults: A Consensus Statement from the Society of Hospital Medicine

Hospital-based clinicians frequently care for patients with opioid withdrawal or opioid use disorder (OUD) and are well-positioned to identify and initiate treatment for these patients. With rising numbers of hospitalizations related to opioid use and opioid-related overdose, the Society of Hospital Medicine convened a working group to develop a Consensus Statement on the management of OUD and associated conditions among hospitalized adults. The guidance statement is intended for clinicians practicing medicine in the inpatient setting (e.g., hospitalists, primary care physicians, family physicians, advanced practice nurses, and physician assistants) and is intended to apply to hospitalized adults at risk for, or diagnosed with, OUD. To develop the Consensus Statement, the working group conducted a systematic review of relevant guidelines and composed a draft statement based on extracted recommendations. Next, the working group obtained feedback on the draft statement from external experts in addiction medicine, SHM members, professional societies, harm reduction organizations and advocacy groups, and peer reviewers. The iterative development process resulted in a final Consensus Statement consisting of 18 recommendations covering the following topics: (1) identification and treatment of OUD and opioid withdrawal, (2) perioperative and acute pain management in patients with OUD, and (3) methods to optimize care transitions at hospital discharge for patients with OUD. Most recommendations in the Consensus Statement were derived from guidelines based on observational studies and expert consensus. Due to the lack of rigorous evidence supporting key aspects of OUD-related care, the working group identified important issues necessitating future research and exploration.

Electrocardiographic Changes in Children With Acute Opioid Poisoning: A Cross-Sectional Study

OBJECTIVES

Opioid poisoning in children is a common pediatric emergency in Iran. The emergence and spread of new synthetic opioids have come up with new consequences in case of toxicity. In this study, we aimed to evaluate electrocardiographic changes in children with acute opiate poisoning.

METHODS

This cross-sectional study was performed on all children with opioid poisoning admitted to the emergency ward of Vali-e-Asr Hospital, Birjand, Iran, from December 2015 to February 2017. Data (demographics, manifestations, clinical course, and outcome) were collected using a predesigned checklist. An electrocardiogram (ECG) was obtained and evaluated for arrhythmias, corrected QT interval (QTc), and other ECG indices. Data were analyzed using SPSS version 21. A value of P less than 0.05 was considered statistically significant.

RESULTS

A total of 85 children were enrolled in this study. Most of them were male (51.8%). The mean age of the patients was 3.46 ± 3.36 years. Among these children, 38.8% were poisoned with synthetic opioids (methadone). Mean QTc length was 399 ± 24 milliseconds in nonsynthetic opioid poisoning and 407 ± 66 milliseconds in methadone poisoning, and it was prolonged (>450 milliseconds) in 3.5% of cases. Other ECG changes were limited to 1 U wave formation (1.2%) that was detected in a patient with methadone poisoning.

CONCLUSIONS

Electrocardiogram changes due to acute opioid toxicity in children are not common, although in the case of methadone poisoning, long QT interval and associated arrhythmias should be anticipated. Moreover, because of life-threatening effects of opioids such as respiratory insufficiency and decreased consciousness, it is necessary to be prepared for these conditions.

Effects of opioid receptor agonist and antagonist medications on electrocardiogram changes and presentation of cardiac arrhythmia: review article

BACKGROUND/PURPOSE

Mortality associated with prescription opioids has significantly increased over the past few decades and is considered a global pandemic. Prescribed opioids can cause cardiac arrhythmias, leading to fatal outcomes and unexpected death, even in the absence of structural cardiac disease. Despite the extent of cardiac toxicity and death associated with these medications, there is limited data to suggest their influences on cardiac electrophysiology and arrhythmias, with the exception of methadone. The goal of our review is to describe the possible mechanisms and to review the different ECG changes and arrhythmias that have been reported.

METHODS

A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct to identify studies that demonstrated the use of prescription opioids leading to electrocardiogram (ECG) changes and cardiac arrhythmias.

RESULTS

Many of the commonly prescribed opioid medications can uniquely effect the ECG, and can lead to the development of various cardiac arrhythmias. One of the most significant side effects of these drugs is QTc interval prolongation, especially when administered to patients with a baseline risk for QTc prolongation. A prolonged QTc interval can cause lethal torsades de pointes and ventricular fibrillation. Obtaining an ECG at baseline, following a dosage increase, or after switching an opioid medication, is appropriate in patients taking certain prescribed opioids. Opioids are often used first line for the treatment of acute and chronic pain, procedural sedation, medication opioid use disorders, and maintenance therapy.

CONCLUSIONS

To reduce the risk of cardiac arrhythmias and to improve patient outcomes, consideration of accurate patient selection, concomitant medications, electrolyte monitoring, and vigilant ECG monitoring should be considered.

Enantiomeric methadone quantitation on real post-mortem dried matrix spots samples: Comparison of liquid chromatography and supercritical fluid chromatography coupled to mass spectrometry

This study describes two bioanalytical methods for the quantitation of the two methadone enantiomers in dried matrix spots using high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) and high performance supercritical chromatography tandem mass spectrometry (HPSFC-MS/MS). Dried matrix spots were obtained by spotting 10 µL of each sample fluid on a Whatman paper. Methadone and its main metabolite, EDDP, were extracted with 100 µL methanol and subsequently injected into the LC-MS/MS and SFC-MS/MS systems. Enantiomeric separation was achieved with AGP-column for the LC conditions and with Chiralpak IH-3 in SFC. The two methods were fully validated and 93 post-mortem samples were analysed with both analytical methods. Results from validation parameters and results obtained for all post-mortem samples were compared with a significant spearman correlation of r_s = 0.9978 for R-methadone and r_s = 0.9981 for S-methadone. The LC method provided better results in terms of uncertainty, retention factor and resolution, whereas SFC provides better sensitivity, with lower LOD. Median R-/S-methadone ratio in peripheral blood was found equal to 1.60 (N = 32), varying from 0.79 to 4.23. The reported values were in good agreement with previously published results. Based on the results obtained here, SFC-MS/MS can be considered a reliable alternative to the widely used LC-MS/MS for the quantitation of methadone enantiomers in bioanalysis and should be evaluated for other bioanalytical methods. Both methods can be easily and quickly used in toxicological routine analysis for the methadone quantitation in human fluids matrices, even if considering that the polysaccharide coated column IH-3 used in SFC does not allow the enantiomeric EDDP separation.

ECG Markers of Cardiovascular Toxicity in Adult and Pediatric Cancer Treatment

When a cardiologist is asked to evaluate the cardiac toxic effects of chemotherapy, he/she can use several tools: ECG, echocardiography, coronary angiography, ventriculography, and cardiac MRI. Of all these, the fastest and easiest to use is the ECG, which can provide information on the occurrence of cardiac toxic effects and can show early signs of subclinical cardiac damage. These warning signs are the most desired to be recognized by the cardiologist, because the dose of chemotherapeutics can be adjusted so that the clinical side effects do not occur, or the therapy can be stopped in time, before irreversible side effects. This review addresses the problem of early detection of cardiotoxicity in adult and pediatric cancer treatment, by using simple ECG recordings.

QTc monitoring in adults with medical and psychiatric comorbidities: Expert consensus from the Association of Medicine and Psychiatry

OBJECTIVE

Several psychiatric medications have the potential to prolong the QTc interval and subsequently increase the risk for ventricular arrhythmias such as torsades de pointes (TdP). There is limited guidance for clinicians to balance the risks and benefits of treatments.

METHODS

After a review of the existing literature, clinical-educators from the Association of Medicine and Psychiatry developed expert consensus guidelines for ECG monitoring of the QTc interval for patients with medical and psychiatric comorbidities who are prescribed medications with the potential to prolong the QTc interval. A risk score was developed based on risk factors for QTc prolongation to guide clinical decision-making.

RESULTS

A baseline ECG may not be necessary for individuals at low risk for arrythmia. Those individuals with a risk score of two or more should have an ECG prior to the start of a potentially QTc-prolonging medication or be started on a lower risk agent. Antipsychotics are not equivalent in causing QTc prolongation. A consensus-based algorithm is presented for the management of those identified at high (QTc >500 msec), intermediate (males with QTc 450-499 msec or females with QTc > 470-499 msec), or low risk.

CONCLUSIONS

The proposed algorithm can help clinicians in determining whether ECG monitoring should be considered for a given patient. These guidelines preserve a role for clinical judgment in selection of treatments that balance the risks and benefits, which may be particularly relevant for complex patients with medical and psychiatric comorbidities. Additional studies are needed to determine whether baseline and serial ECG monitoring reduces mortality.

Effect of Methadone on Cardiac Repolarization in Japanese Cancer Patients: A Longitudinal Study

INTRODUCTION

Methadone is known to prolong the QT interval, which could induce lethal arrhythmias such as torsades de pointes. To determine the risk of ventricular arrhythmias in cancer patients using methadone, we measured QT dispersion (QTD) and Tpeak-Tend (TpTe) before and after methadone administration and evaluated the correlations between methadone dosage and cardiac repolarization.

METHODS

We conducted a retrospective observational study with 19 patients undergoing follow-up for cancer pain with methadone. Electrocardiogram (ECG) recordings were obtained from the patients at methadone initiation and 1 week, 1 month, and 2 months later. The QT, corrected QT (QTc), QTD, QTc dispersion (QTcD), TpTe, TpTe/QT, and TpTe/QTc were measured manually via ECG records and analyzed using a repeated measures one-way ANOVA. The correlations between these ECG parameters and each methadone dosage were determined using Spearman's rank correlation coefficient.

RESULTS

The QTD, QTcD, TpTe/QT, and TpTe/QTc remained unchanged, while TpTe was prolonged significantly at 2 months (initiation: 82 ± 17 ms; 2 months: 106 ± 20 ms, p = 0.018). In addition, there was a positive correlation between TpTe and methadone dosage (rs = 0.4, p = 0.041).

CONCLUSIONS

The findings suggested that small or modest doses of methadone could exert dose-dependent effects on cardiac repolarization in cancer patients.

TRIAL REGISTRATION

UMIN Clinical Trials Registry, UMIN000034519.

Integrating in vitro data and physiologically based kinetic modeling-facilitated reverse dosimetry to predict human cardiotoxicity of methadone

Development of novel testing strategies to detect adverse human health effects is of interest to replace in vivo-based drug and chemical safety testing. The aim of the present study was to investigate whether physiologically based kinetic (PBK) modeling-facilitated conversion of in vitro toxicity data is an adequate approach to predict in vivo cardiotoxicity in humans. To enable evaluation of predictions made, methadone was selected as the model compound, being a compound for which data on both kinetics and cardiotoxicity in humans are available. A PBK model for methadone in humans was developed and evaluated against available kinetic data presenting an adequate match. Use of the developed PBK model to convert concentration–response curves for the effect of methadone on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) in the so-called multi electrode array (MEA) assay resulted in predictions for in vivo dose–response curves for methadone-induced cardiotoxicity that matched the available in vivo data. The results also revealed differences in protein plasma binding of methadone to be a potential factor underlying variation between individuals with respect to sensitivity towards the cardiotoxic effects of methadone. The present study provides a proof-of-principle of using PBK modeling-based reverse dosimetry of in vitro data for the prediction of cardiotoxicity in humans, providing a novel testing strategy in cardiac safety studies.

Association of QT dispersion with mortality and arrhythmic events-A meta-analysis of observational studies

BACKGROUND

The risk stratification of coronary heart disease (CHD) and/or heart failure (HF) patients with easily measured electrocardiographic markers is of clinical importance. The aim of this meta-analysis is to indicate whether increased QT dispersion (QTd) is associated with fatal and nonfatal outcomes in patients with CHD and/or HF.

METHODS

We systematically searched MEDLINE and Cochrane databases without restrictions until August 15, 2018 using the keyword "QT dispersion". Studies including data on the association between QTd and all-cause mortality, sudden cardiac death (SCD) or arrhythmic events in patients with HF and/or CHD were classified as eligible.

RESULTS

In the analysis including patients with CHD and/or HF, we found that QTd did not differ significantly in patients with SCD compared to no SCD patients while QTd was significantly greater in the group of all-cause mortality patients and in patients who experienced a sustained ventricular arrhythmia. Subgroup analysis showed that in myocardial infarction studies, QTd was significantly higher in patients with an arrhythmic event compared to arrhythmic event-free patients while a nonsignificant difference was found in QTd in patients who died from any cause compared to survivors. Similarly, in HF patients, the QTd was significantly greater in patients with an arrhythmic event while a nonsignificant difference was found regarding all-cause mortality and SCD outcomes.

CONCLUSIONS

QTd has a prognostic role for stratifying myocardial infarction or HF patients who are at higher risk of arrhythmic events. However, no prognostic role was found regarding all-cause mortality or SCD in this patient population.

Medications for management of opioid use disorder

Purpose

The use of buprenorphine, methadone, and long-acting naltrexone for treatment of opioid use disorder (OUD) is discussed, including a review of current literature detailing treatment approaches and action steps to optimize treatment in acute care and office-based settings.

Summary

The U.S. epidemic of opioid-related deaths has been driven by misuse of prescription opioids and, increasingly, illicit drugs such as heroin, fentanyl, and fentanyl analogs, necessitating a refocusing of treatment efforts on expanding access to life-saving, evidence-based OUD pharmacotherapy. Inpatient treatment of opioid withdrawal includes acute symptom control through a combination of nonopioid medications and long-term pharmacotherapy to lessen opioid craving and facilitate stabilization and recovery. Methadone and buprenorphine reduce opioid craving, increase treatment retention, reduce illicit opioid use, and increase overall survival. Buprenorphine has logistical advantages over methadone, such as greater flexibility of treatment setting and less risk of adverse effects. Studies have shown the efficacy of long-acting injectable naltrexone to be comparable to that of buprenorphine if patients are detoxified prior to initiation of therapy; however, patients with active OUD are often not able to complete the week-long period of opioid abstinence needed prior to initiation of naltrexone injections. Although buprenorphine is preferred by many patients and can be prescribed in office-based settings, there remains a paucity of physicians certified to prescribe it.

Conclusion

Buprenorphine has become the medication of choice for many patients with OUD, but its use is limited by the low number of physicians certified to prescribe the agent. Other agents studied for treatment of OUD include methadone and naltrexone.

Drug-induced prolonged corrected QT interval in patients with methadone and opium overdose

BACKGROUND

Iran is a country with the highest rate of opioid addiction in the world. The most commonly used opioid in Iran is opium, and methadone is in second place. The trend of drug use has changed from opium to methadone from 2006 to 2011. Presence of a large number of addicted people and methadone maintenance therapy clinics make methadone readily available in Iran. Therefore, evaluation of the epidemiological characteristic of methadone toxicity and its effects on the heart is essential.

METHODS

In This cross-sectional, retrospective, descriptive, analytical study all patients with methadone or opium toxicity who had been admitted to Vasei hospital, Sabzevar, Iran, during the years 2015 and 2016 were included, and their records were evaluated. Demographic data, addiction history, underlying diseases, and the outcome of admission were recorded. Then, corrected QT interval (QTc) of the first ECG of the patients after admission was evaluated.

RESULTS

The Majority of toxicities occurred in those above 30 years of age (71.4%), who lived in cities (62.8%), and were married (69.2%). A positive history of addiction was considerably higher in the opium group (72.3% versus 43.3%). There was no significant difference regarding QTc prolongation between patients with methadone and opium toxicity (p = 0.3).

CONCLUSION

QTc prolongation is one of the adverse effects of methadone or opium overdose. It seems that significant QTc prolongation is not uncommon among patients with opium overdose.

Opioids and Cardiac Arrhythmia: A Literature Review

OBJECTIVE

One of the most important side effects of opioids is their influence on the electrical activity of the heart. This review focusses on the effects of opioids on QT interval prolongation and their arrhythmogenic liability.

METHODS

By using various keywords, papers published up to 2018 in different databases were searched and identified. The search terms were opioids names, corrected QT interval, human-ether-a-go-go gene, torsades de pointes (TdP), cardiac arrhythmias, opioid dependence and other relevant terms. It emphasized the effects of each opioid agent alone on electrocardiogram (ECG) and some interactions.

RESULTS

Available data indicate that some opioids such as methadone are high-risk even at low doses, and have potential for prolongation of the QT interval and development of TdP, a dangerous ventricular tachycardia. A number of opioids such as tramadol and oxycodone are intermediate risk drugs and may develop long QT interval and TdP in high doses. Some other opioids such as morphine and buprenorphine are low-risk drugs and do not produce QT interval prolongation and TdP at least in routine doses. Opium-consumers are at higher risk of supra-ventricular arrhythmias, sinus bradycardia, cardiac block and atrial fibrillation.

CONCLUSION

The cardiac arrhythmogenicity of various opioids is different. Methadone has a higher capability to induce long QT interval and dangerous arrhythmias in conventional doses than others. To reduce of arrhythmogenic risk, high doses of opioids must be used cautiously with periodic monitoring of ECG in high-risk consumers such as patients under opioid maintenance treatment.

Methadone prolongs cardiac conduction in young patients with cancer-related pain

OBJECTIVE

Methadone prolongs cardiac conduction, from mild corrected QT (QTc) prolongation to torsades de pointes and ventricular fibrillation, in adults. However, methadone use for pain and its effects on cardiac conduction have not been investigated in pediatric populations.

METHODS

A retrospective review of QTc intervals in patients receiving methadone analgesia was conducted. Medical records from a 4-year period (September 2006 to October 2010) at a pediatric oncology institution were reviewed, and correlations were tested between cardiac conduction and methadone dosage and duration of therapy, electrolyte levels, renal and hepatic dysfunction, and concurrent medications.

RESULTS

Of the 61 patients who received methadone, 37 met our inclusion criteria and underwent 137 electrocardiograms (ECGs). During methadone treatment, the mean QTc was longer than that at baseline (446.5 vs 437.55 ms). The mean methadone dose was 27.0±24.3 mg/d (range, 5-125 mg/d; median, 20 mg/d) or 0.47±0.45 mg/kg per day (range, 0.05-2.25 mg/kg per day; median, 0.37 mg/kg per day), and the mean duration of therapy was 49 days. The authors identified a correlation between automated and manual ECG readings by two cardiologists (Pearson r=0.649; p<0.0001), but the authors found no correlations between methadone dose or duration and concurrent QTc-prolonging medications, sex, age, electrolyte abnormalities, or renal or hepatic dysfunction.

CONCLUSION

At a clinically effective analgesic dose, methadone dosage and duration were not correlated with QTc prolongation, even in the presence of other risk factors, suggesting that methadone use may be safe in pediatric populations. The correlation between automated and manual ECG readings suggests that automated ECG readings are reliable for monitoring cardiac conductivity during the reported methadone-dosage regimens.

Perioperative management in children with chronic pain

Children with chronic pain often undergo surgery and effective perioperative management of their pain can be challenging. Identification of the pediatric chronic pain patient preoperatively and development of a perioperative pain plan may help ensure a safer and more comfortable perioperative course. Successful management usually requires multiple different classes of analgesics, regional anesthesia, and adjunctive nonpharmacological therapies. Neuropathic and oncological pain can be especially difficult to treat and usually requires an individualized approach.

The Impact of Opioids on Cardiac Electrophysiology

Synthetic opioid agents have been used in modern medicine for over a century and for opioid addiction treatment for over a half-century. Liberal use of opioids in the United States has been attended by an extraordinary increase in opioid-related mortality, with over 16,000 deaths in 2012. As there have been advances in opioid agents for pain and addiction, so have there been advances in our understanding of the cardiac effects of these agents. In the last 10 years, significant data regarding electrophysiologic effects of these agents have been collected. We aim in this review to discuss the effects on cardiac electrophysiology of the various opioid agents currently in use and the evidence that these effects are contributing to the rise in opioid-related mortality.

Methadone Therapy in Underserved Urban Community: QTc Prolongation and Life-Threatening Ventricular Arrhythmias

AIMS

Methadone has been associated with QTc prolongation and ventricular arrhythmias but the prevalence of QTc prolongation and association with ventricular arrhythmias remains unclear. We investigated this in our inner city urban community (Bronx, New York) that has a large number of patients on methadone.

METHODS

Telemetry records, nursing documentation and electronic charts of 291 patients spanning856 encounters were evaluated. QT was manually measured from ECG utilizing standardized QT measurement guidelines and was corrected for heart rate using Hodges formula. QTc >470 ms in males and >480 ms in females was considered to be prolonged.

RESULTS

Patients had prolonged QTc, QTc >500 ms and ventricular arrhythmias during 25.6%, 14.1% and 3.4% of encounters, respectively. There was a very weak dose dependent relationship between methadone dose and QTc (Spearman's rho = 0.09).In addition to methadone, patients were on at least one QT prolonging drugs during 39% of the encounters. Patients who were receiving two interacting drugs in addition to methadone had the highest prevalence (29%) of QTc prolongation.

CONCLUSION

Although the prevalence of QTc prolongation among patients on methadone therapy is high, the prevalence of ventricular arrhythmia is relatively low. Hospitalized patients on sustained methadone therapy are frequently on multiple additional QTc prolonging drugs. There is no significant dose dependent relationship between methadone dose and QTc. However, the concurrent use of methadone and interacting drugs lead to an increased prevalence of QTc prolongation.

The correlation between prolonged corrected QT interval with the frequency of respiratory arrest, endotracheal intubation, and mortality in acute methadone overdose

Corrected QT interval (QTc) prolongation is long considered as a predisposing factor for the occurrence of torsade de pointes (TdP) and sudden cardiac arrest in methadone maintenance treatment. We aimed to elucidate the correlation between QTc prolongation and in-hospital death, respiratory arrest, and endotracheal intubation in acute methadone-intoxicated patients presenting to the emergency department and to assess the value of QTc in predicting these outcomes. A prospective cross-sectional study with a convenience sample of patients with acute methadone overdose was done. Participants were 152 patients aged 15-65 with negative urinary dipstick test for cyclic antidepressants, no history of other QTc-prolonging conditions and co-ingestions, no severe comorbidities affecting the outcomes, and positive urinary dipstick results for methadone. QTc intervals were measured and calculated in triage-time electrocardiogram (ECG). Death was correlated with QTc (P = 0.014) and length of ICU admission (P < 0.001). In multivariable analysis, death was independently associated only with length of ICU admission [odds ratio (OR) 95 % confidence intervals (95 % CI) 1.36 (1.14-1.61)]. Intubation and respiratory arrest were independently associated with QTc interval [OR (95 % CI) 1.03 (1.02-1.04) and 1.02 (1.01-1.03), respectively]. The receiver operating characteristics curves drawn to show the ability of QTc to predict death, intubation, and respiratory arrest showed thresholds of 470, 447.5, and 450 ms with sensitivity (95 % CI) and specificity (95 % CI) of 87.5 (47.3-99.7), 86.8 (74.7-94.5), and 77.3 (62.2-88.5), respectively. Our study showed that QTc is a potential predictor for adverse outcomes related to acute methadone intoxication. The correlations shown in this study between triage-time QTc and in-hospital respiratory arrest or intubation in methadone overdose may be of clinical value, whether these outcomes are hypothesized to be a reflection of background TdP or intoxication severity.

A systematic review of the cardiotoxicity of methadone

Methadone is one of the most popular synthetic opioids in the world with some favorable properties making it useful both in the treatment of moderate to severe pain and for opioid addiction. Increased use of methadone has resulted in an increased prevalence of its toxicity, one aspect of which is cardiotoxicity. In this paper, we review the effects of methadone on the heart as well as cardiac concerns in some special situations such as pregnancy and childhood.

METHODS

We searched for the terms methadone, toxicity, poisoning, cardiotoxicity, heart, dysrhythmia, arrhythmia, QT interval prolongation, torsade de pointes, and Electrocardiogram (ECG) in bibliographical databases including TUMS digital library, PubMed, Scopus, and Google Scholar. This review includes relevant articles published between 2000 and 2013. The main cardiac effects of methadone include prolongation of QT interval and torsade de pointes. Other effects include changes in QT dispersion, pathological U waves, Taku-Tsubo syndrome (stress cardiomyopathy), Brugada-like syndrome, and coronary artery diseases. The aim of this paper is to inform physicians and health care staff about these adverse effects. Effectiveness of methadone in the treatment of pain and addiction should be weighed against these adverse effects and physicians should consider the ways to lessen such undesirable effects. This article presents some recommendations to prevent heart toxicity in methadone users.

Electrocardiographic findings in systemic lupus erythematosus: data from an international inception cohort

OBJECTIVE

To estimate the early prevalence of various electrocardiographic (EKG) abnormalities in patients with systemic lupus erythematosus (SLE) and to evaluate possible associations between repolarization changes (increased corrected QT [QTc] and QT dispersion [QTd]) and clinical and laboratory variables, including the anti-Ro/SSA level and specificity (52 or 60 kd).

METHODS

We studied adult SLE patients from 19 centers participating in the Systemic Lupus International Collaborating Clinics (SLICC) Inception Registry. Demographics, disease activity (Systemic Lupus Erythematosus Disease Activity Index 2000 [SLEDAI-2K]), disease damage (SLICC/American College of Rheumatology Damage Index [SDI]), and laboratory data from the baseline or first followup visit were assessed. Multivariate logistic and linear regression models were used to asses for any cross-sectional associations between anti-Ro/SSA and EKG repolarization abnormalities.

RESULTS

For the 779 patients included, mean ± SD age was 35.2 ± 13.8 years, 88.4% were women, and mean ± SD disease duration was 10.5 ± 14.5 months. Mean ± SD SLEDAI-2K score was 5.4 ± 5.6 and mean ± SD SDI score was 0.5 ± 1.0. EKG abnormalities were frequent and included nonspecific ST-T changes (30.9%), possible left ventricular hypertrophy (5.4%), and supraventricular arrhythmias (1.3%). A QTc ≥440 msec was found in 15.3%, while a QTc ≥460 msec was found in 5.3%. Mean ± SD QTd was 34.2 ± 14.7 msec and QTd ≥40 msec was frequent (38.1%). Neither the specificity nor the level of anti-Ro/SSA was associated with QTc duration or QTd, although confidence intervals were wide. Total SDI was significantly associated with a QTc interval exceeding 440 msec (odds ratio 1.38 [95% confidence interval 1.06, 1.79]).

CONCLUSION

A substantial proportion of patients with recent-onset SLE exhibited repolarization abnormalities, although severe abnormalities were rare.

Research gaps on methadone harms and comparative harms: findings from a review of the evidence for an American Pain Society and College on Problems of Drug Dependence clinical practice guideline

Methadone-associated overdose deaths have dramatically increased. In order to inform an evidence-based clinical practice guideline to improve safety of methadone prescribing, the American Pain Society commissioned a systematic review on various aspects related to methadone safety. We searched Ovid MEDLINE, Cochrane Library, and PsycINFO databases through July 2012 to identify studies that addressed 1 or more of 17 Key Questions related to methadone safety; an update search was performed in 2014 for new studies related to methadone-related overdose and risks related to cardiac arrhythmias. A total of 168 studies met inclusion criteria for the review. The purpose of this article is to highlight critical research gaps in the literature related to methadone safety. These include lack of evidence on risk factors associated with methadone-overdose deaths and adverse events, limited evidence to evaluate the comparative mortality of methadone versus other opioids, insufficient evidence to fully understand the harms associated with methadone use during pregnancy, and insufficient evidence to determine effects of risk mitigation strategies such as electrocardiogram monitoring, strategies for managing patients with prolonged QTc intervals on screening, urine drug testing, alternative dosing regimens for initiation and titration of therapy, and timing of follow-up. Therefore, most guideline recommendations are based on weak evidence. More research is needed to guide safe methadone prescribing practices and decrease the adverse events associated with methadone.

PERSPECTIVE

This article summarizes critical research gaps in the literature related to methadone safety, based on a systematic review commissioned by the American Pain Society. Critical research gaps were identified in a number of areas, highlighting the need for additional research to guide safer prescribing and risk mitigation strategies.

Methadone safety: a clinical practice guideline from the American Pain Society and College on Problems of Drug Dependence, in collaboration with the Heart Rhythm Society

Methadone is used for the treatment of opioid addiction and for treatment of chronic pain. The safety of methadone has been called into question by data indicating a large increase in the number of methadone-associated overdose deaths in recent years that has occurred in parallel with a dramatic rise in the use of methadone for chronic pain. The American Pain Society and the College on Problems of Drug Dependence, in collaboration with the Heart Rhythm Society, commissioned an interdisciplinary expert panel to develop a clinical practice guideline on safer prescribing of methadone for treatment of opioid addiction and chronic pain. As part of the guideline development process, the American Pain Society commissioned a systematic review of various aspects related to safety of methadone. After a review of the available evidence, the expert panel concluded that measures can be taken to promote safer use of methadone. Specific recommendations include the need to educate and counsel patients on methadone safety, use of electrocardiography to identify persons at greater risk for methadone-associated arrhythmia, use of alternative opioids in patients at high risk of complications related to corrected electrocardiographic QTc interval prolongation, careful dose initiation and titration of methadone, and diligent monitoring and follow-up. Although these guidelines are based on a systematic review, the panel identified numerous research gaps, most recommendations were based on low-quality evidence, and no recommendations were based on high-quality evidence.

PERSPECTIVE

This guideline, based on a systematic review of the evidence on methadone safety, provides recommendations developed by a multidisciplinary expert panel. Safe use of methadone requires clinical skills and knowledge in use of methadone to mitigate potential risks, including serious risks related to risk of overdose and cardiac arrhythmias.

Methadone overdose and cardiac arrhythmia potential: findings from a review of the evidence for an American Pain Society and College on Problems of Drug Dependence clinical practice guideline

The number of deaths associated with methadone use increased dramatically in parallel with marked increases in its use, particularly for treatment of chronic pain. To develop a clinical guideline on methadone prescribing to reduce potential harms, the American Pain Society commissioned a review of various aspects related to methadone safety. This article summarizes evidence related to unintentional overdose due to methadone and harms related to cardiac arrhythmia potential. We searched Ovid MEDLINE, the Cochrane Library, and PsycINFO databases through January 2014 for studies assessing harms associated with methadone use; we judged 70 studies to be relevant and to meet inclusion criteria. The majority of studies on overdose and cardiac arrhythmia risk are observational and provide weak evidence on which to base clinical guidelines. In patients prescribed methadone for treatment of opioid dependence, data suggest that mortality benefits related to reduction in illicit drug use outweigh harms. Despite epidemiologic data showing marked increases in the numbers of methadone-related deaths that have been primarily attributed to increased use of methadone for chronic pain, evidence on methadone and mortality risk in this population has been somewhat contradictory. There is some evidence that recent initiation of methadone, psychiatric admissions, and concomitant use of benzodiazepines are associated with a higher risk for overdose. Evidence on cardiac risks is primarily limited to case reports of torsades de pointes, primarily in patients on high doses of methadone, and to studies showing an association between methadone use and prolongation of QTc intervals. Research is needed to understand the effectiveness of dosing methods, electrocardiogram monitoring, and other risk mitigation strategies in patients prescribed methadone.

PERSPECTIVE

This systematic review synthesizes the evidence related to methadone use and risk for overdose and cardiac arrhythmia. Findings regarding the association between methadone use and QTc interval prolongation and risk factors for methadone-associated overdose suggest potential targets for risk mitigation strategies, though research is needed to determine the effectiveness of such strategies at reducing adverse outcomes.

The impact of recent cocaine use on plasma levels of methadone and buprenorphine in patients with and without HIV-infection

Cocaine decreases methadone and buprenorphine plasma concentrations. HIV infection and/or antiretroviral medication use may impact these relationships. We sought to determine the association between recent cocaine use and methadone and buprenorphine concentrations in HIV-infected and uninfected subjects in clinical care. R- and S-methadone or buprenorphine and norbuprenorphine concentrations were assessed at 0.5, 1, 2, and 24 hours after dosing in subjects with confirmed cocaine use and abstinence. We compared methadone and buprenorphine concentrations for cocaine use vs. abstinence, by HIV status in 16 subjects receiving methadone (6 HIV-infected) and 17 receiving buprenorphine (8 HIV-infected). With recent cocaine use, peak R-methadone (244 vs. 297 ng/mL, p = 0.03) and peak S-methadone (285 vs. 339 ng/mL); p = 0.03 concentrations were lower in HIV-uninfected subjects only. Peak buprenorphine and norbuprenorphine concentrations were unchanged regardless of cocaine use or HIV status. Cocaine may decrease methadone concentrations in HIV-uninfected subjects. HIV infection or its treatment may attenuate cocaine's effect on methadone.

Methadone for pain and the risk of adverse cardiac outcomes

CONTEXT

There are few studies that describe cardiac adverse events in patients prescribed methadone for pain management.

OBJECTIVES

To describe incident cardiac adverse events and risk factors for cardiac adverse events in primary care patients prescribed methadone for pain.

METHODS

This was a retrospective, descriptive, cohort study in patients 18 years or older receiving methadone for pain management during 2010. Patients were followed for 12 months and were categorized as "chronic" or "non-chronic" methadone users. The primary outcomes were a cardiac event, at risk for an event, or neither. Patients were grouped on their outcome and were compared on risk factors and methadone monitoring.

RESULTS

A total of 1246 patients were included. Thirty (2.4%), 628 (50.4%), and 588 (47.2%) patients had a cardiac event, were at risk for an event, or had neither an event nor a risk factor, respectively. Overall, the rate of QTc prolongation was 49.4% and the rate of adherence to recommended cardiac monitoring was 39.0%. Similar percentages of chronic and non-chronic users had a cardiac event (P > 0.05). Among the patients who had a cardiac event and were at risk for an event, factors independently associated with having had an event included age (odds ratio = 1.06; 95% CI = 1.03-1.09) and a dose 100 mg/day or higher (odds ratio = 6.18; 95% CI = 1.08-35.45).

CONCLUSION

Few cardiac adverse events resulting from methadone use for pain were detected. However, a large proportion of patients were at risk for an adverse event, especially patients who were older and had received ≥ 100 mg/day of methadone.

Drug-induced cardiovascular adverse events in the intensive care unit

Critically ill patients are at high risk of adverse drug events during their intensive care unit stay. Of the potential adverse drug events, those related to the cardiovascular system are particularly concerning. Common cardiovascular adverse drug events include drug-induced arrhythmias, drug-induced blood pressure abnormalities, and drug-induced heart failure. The specific drug-induced events to be reviewed include bradycardia, tachycardia, corrected QT interval prolongation, hypertension, hypotension, and heart failure exacerbation.

Effects of disulfiram on QTc interval in non-opioid-dependent and methadone-treated cocaine-dependent patients

OBJECTIVES

Methadone and cocaine are each known to prolong the QTc interval, a risk factor for developing potentially fatal cardiac arrhythmias. Disulfiram, often administered in the context of methadone maintenance to facilitate alcohol abstinence, has been shown to have some efficacy for cocaine dependence. Disulfiram has differential effects on cocaine and methadone metabolism, but its impact on methadone- or cocaine-induced changes in QTc interval is unclear. Thus, the effects of disulfiram on QTc interval in a subset of cocaine-dependent patients participating in a 14-week, randomized, double-blind, placebo-controlled clinical trial of disulfiram were prospectively determined.

METHODS

Opioid-dependent participants were inducted onto methadone (weeks 1-2; MT) and both MT and non-opioid-dependent (UT) participants were randomized to receive disulfiram (weeks 3-14) at one of the following doses: 0, 250, 375, or 500 mg/d. Electrocardio-grams were obtained before study entry and during weeks 2 and 4.

RESULTS

Complete QTc-interval data in 23 MT and 18 UT participants were analyzed. QTc interval tended to be higher in MT participants relative to UT participants, regardless of disulfiram dose and time point, but disulfiram did not differentially alter QTc interval. QTc interval was, however, significantly greater in participants with recent cocaine use than in those with no recent use.

CONCLUSIONS

These results suggest that cocaine use and possibly MT status, but not disulfiram, are risk factors for QTc prolongation.

Methadone, QTc prolongation and torsades de pointes: Current concepts, management and a hidden twist in the tale?

Methadone is a drug that has found widespread utility in the management of opioid addiction and pain. Along with its popularity, methadone has also earned an infamous reputation for causing prolongation of the QT interval and an increased risk of torsades de pointes. In this article we will give a brief overview of the long QT syndromes, followed by an in-depth look at the current pathophysiologic mechanisms of methadone induced QT prolongation, a review of the existing literature and the current concepts regarding the prevention and management of methadone induced torsades de pointes. In addition, we explore the idea and implications of a genetic link between methadone induced prolongation of the QT interval and torsades de pointes.

Methadone, QTc interval prolongation and torsade de pointes: Case reports offer the best understanding of this problem

We reviewed the literature and found 31 adult cases and 1 newborn case of methadone-associated QTc interval prolongation and/or torsade de pointes (TdP). Parametric statistics may not be useful in studying this issue because methadone-associated TdP is a very rare event and, hence, "an extreme outlier" consistent with scalable randomness. We may have to rely upon narrative medicine in the form of case reports with all its limitations and hazards to provide our best understanding. We report risk factors for methadone-associated QTc interval prolongation and TdP based on review of published case reports. We believe both drug manufacturers and the FDA would better serve our patients and inform clinicians if they more readily reported drug-induced outliers such as methadone-associated TdP using a case report format.

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

BACKGROUND

Methadone represents today the gold standard of efficacy for the pharmacological treatment of opioid dependence. Methadone, like many other medications, has been implicated in the prolongation of the rate-corrected QT (QTc) interval of the electrocardiogram (ECG), which is considered a marker for arrhythmias such as torsade de pointes (TdP). Indications on the association between methadone, even at therapeutic dosages, and TdP or sudden cardiac death have been reported. On these bases, consensus and recommendations involving QTc screening of patients receiving methadone treatment have been developed to identify patients with QTc above the thresholds considered at risk for cardiac arrhythmias, and they provide these individuals with alternative treatment (reduction of methadone dosage; provision of alternative opioid agonist treatment; treatment of associated risk factors).

OBJECTIVES

To evaluate the efficacy and acceptability of QTc screening for preventing cardiac-related morbidity and mortality in methadone-treated opioid dependents.

SEARCH METHODS

We searched MEDLINE, EMBASE, CINAHL (to April 2013), the Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library Cochrane Drug and Alcohol Review Group Specialised Register (Issue 3, 2013), main electronic sources of ongoing trials, specific trial databases and reference lists of all relevant papers.

SELECTION CRITERIA

Randomised controlled trials (RCTs), controlled clinical trials (CCTs) and non-randomised studies (cohort studies, controlled before and after studies, interrupted time series studies, case control studies) examining the efficacy of QTc screening for the prevention of methadone-related mortality and morbidity in opioid addicts.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and extracted data from studies.

MAIN RESULTS

The search strategy led to the identification of 872 records. Upon full-text assessment, no study was found to meet the quality criteria used for this review.

AUTHORS' CONCLUSIONS

It is not possible to draw any conclusions about the effectiveness of QTc screening strategies for preventing cardiac morbidity/mortality in methadone-treated opioid addicts. Research efforts should focus on strengthening the evidence about the effectiveness of widespread implementation of such strategies and clarifying the associated benefits and harms.

Tramadol versus methadone for treatment of opiate withdrawal: a double-blind, randomized, clinical trial

The aim of this study was to compare the efficacy and safety of tramadol versus methadone for treatment of opiate withdrawal. Seventy patients randomly were assigned in two groups to receive either prescribed methadone (60 mg/day) or tramadol (600 mg/day). The withdrawal syndrome of patients was evaluated before and after rapid opiate detoxification using the Objective Opioid Withdrawal Scale (OOWS). No significant differences existed in overall OOWS scores between two groups (P = 0.11). Dropout rates were similar in both groups. Side effects in the tramadol group were as or less common than in the methadone group, with the exception of perspiration. Tramadol may be as effective as methadone in the control of withdrawal and could be considered as a potential substitute for methadone to manage opioids withdrawal.

QT interval screening in methadone maintenance treatment: report of a SAMHSA expert panel

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.

Physical and mental health in severe opioid-dependent patients within a randomized controlled maintenance treatment trial

AIMS

To evaluate physical and mental health and compare treatment outcomes in opiate-dependent patients substituted either with heroin or methadone.

DESIGN

Twelve-month open-label randomized controlled trial.

SETTING

Out-patient substitution clinics in seven German cities.

PARTICIPANTS

A total of 1015 opiate-dependent individuals.

MEASUREMENTS

Opiate Treatment Index-Health Scale Score (OTI), Body Mass Index (BMI), serology for infectious diseases such as hepatitis B, C and human immunodeficiency virus as well as tuberculosis, Karnofsky Performance Scale (KPS), electrocardiogram (ECG), echocardiogram, Symptom Checklist 90-R (SCL-90-R), Global Assessment of Functioning (GAF), Modular System for Quality of Life and study medication-related serious adverse events (SAE).

FINDINGS

Improvements were found in both heroin and methadone substituted patients regarding OTI, BMI, KPS, SCL-90-R, and GAF, but they were more pronounced for the heroin group (analysis of variance, all P = 0.000). The frequency of pathological echocardiograms decreased in the heroin group and increased in the methadone group (χ(2) test, <0.05). Markers for infectious diseases and frequencies of pathological ECGs did not differ between baseline and 12 months, or between treatment groups. Study medication-related serious adverse events, all of which were treated successfully, occurred 2.5 times more often in the heroin group. The majority of heroin-related SAEs (41 of 58) occurred within a few minutes of the injections.

CONCLUSIONS

The integration of severe injection drug users either in methadone or heroin-assisted maintenance treatment has positive effects on most physical and mental change-sensitive variables, with heroin showing superior results. Due to medication-related adverse events, patients should be observed for 15 minutes after a heroin injection.

[Review of cases of prolonged QTC and wave burst arrhythmia in patients treated with methadone]

INTRODUCTION

For the past 40 years, methadone has been known to be an efficient treatment of substitution. Its use allowed a significant reduction in the mortality related to opioid addiction. Since 2001, many articles have reported some cases of syncope, wave burst arrhythmia, ventricular tachycardia due to prolonged QT interval and sudden death secondary to cardiac arrest, with a risk of prolongation of the QT interval above 440 ms (men) and 460 ms (women). Many explorations have helped in understanding the physiopathology by showing that opioids, including methadone, cause a blockage of the potassium channels of the gene HERG K+P. This event could slow the repolarisation and the atrioventricular cardiac synchronization and could induce ventricular arrhythmia.

LITERATURE FINDINGS

Nearly 20 studies showed a prolonged QT interval secondary to methadone in patients exhibiting the following features: (1) patients with cardiac pathologies, notably bradycardia, congenital long QT interval, myocardial pathologies related to AIDS and electrolyte disturbances; (2) patients receiving concomitant treatment with substances known to prolong QT interval, such as psychoactive stimulants, narcoleptics, tricyclic antidepressants, antiarrhythmic agents, macrolids, quinolones, non diuretic hypokalemiants and certain corticoids; (3) patients receiving treatments that inhibit methadone's metabolism, particularly those that act on the cytochrome P450 3A4 such as SSRI, antifungal agents, some macrolids and some retroviral agents. Many recent studies, while evaluating the dose-dependent effect of methadone on the QT prolongation, showed a tendency to a prolonged QT when using higher doses of methadone.

CONCLUSION

Screening for these risk factors should be carried out before prescribing methadone. EKG should not be systematically performed unless the conditions described above are present or if a higher dose of methadone is needed.

QT interval prolongation: prevalence, risk factors and pharmacovigilance data among methadone-treated patients in France

Several reports have suggested the role of methadone in QT prolongation, Torsades de Pointes (TdP), and ventricular arrhythmia. The aim of this study was to identify the frequency of QT interval prolongation and QT dispersion among a population of addict patients treated with methadone, completed by the description of cardiac events reported to the French pharmacovigilance system. QT interval (corrected with the Bazett's method) and dispersion were measured on a cohort of patients treated with methadone during their visit to addiction specialized centers in Southwest of France. Whenever possible, methadone blood concentrations were measured. In addition, reports concerning methadone were searched in the French Pharmacovigilance database from 1996 to 2007. The cohort included 42 patients with mean QTc length of 414.3 ± 28.5 ms and mean QT dispersion of 66.0 ± 41.1 ms. None of the patient presented a QTc above 500 ms. These values were higher in patients with recent increase in methadone dose, use of tobacco or drugs prolonging QT, and history of cardiac disease. We found five cases of QT prolongation (3 TdP) and seven cases of sudden deaths in the French pharmacovigilance database (2.2% of methadone reports). Most of these events occurred after introducing methadone or another drug potentially interacting with methadone. Methadone can prolong the QT interval at dose usually used for addiction maintenance treatment in France. A cardiac evaluation, with at least a systematic ECG, could be useful during methadone treatment, particularly in case of recent modification of the regimen.

Itraconazole-induced torsade de pointes in a patient receiving methadone substitution therapy

ISSUES

Methadone, a pharmacological agent used to treat heroin dependence is relatively safe, but may cause cardiac arrhythmias in the concurrent presence of other risk factors. APPROACH AND KEY FINDINGS: This case report highlights the risk of torsade de pointes, a life-threatening cardiac arrhythmia, in a heroin-dependent patient receiving methadone substitution therapy who was prescribed itraconazole for vaginal thrush. The patient presented to the accident and emergency department for chest discomfort and an episode of syncope following two doses of itraconazole (200 mg). Electrocardiogram monitoring at the accident and emergency department showed prolonged rate-corrected QT interval leading to torsade de pointes. The patient was admitted for cardiac monitoring, and electrocardiogram returned to normal upon discontinuation of methadone.

IMPLICATION

This cardiac arrhythmia was most likely as a result of a drug interaction between methadone and itraconazole because the patient presented with no other risk factors.

CONCLUSION

Given the benefits of methadone as a substitution treatment for heroin-dependent individuals, the association between methadone and cardiac arrhythmias is of great concern. Physicians treating heroin-dependent patients on methadone substitution therapy should therefore be cautious of the potential risk of drug interactions that may lead to fatal cardiac arrhythmias.

Retrospective analysis of low-dose methadone and QTc prolongation in chronic pain patients

Background

Methadone is a synthetic opioid that is widely used for the treatment of chronic pain. The association between methadone treatment and QT interval prolongation or which can lead to torsades de pointes has been confirmed with larger studies on high dose methadone. The aim of this study was to determine the effect of methadone on the QTc interval in patients, whether the daily dose of methadone should be lower than what has been previously investigated.

Methods

A total of 130 patients were included, with 90 patients in the methadone group and 40 patients in the control group. For each ECG, heart rate, QT interval and corrected QT (QTc) interval were recorded. The patient demographics, methadone dose and serum level, duration of methadone use and past medical history were collected.

Results

The QTc interval was significantly longer in the treatment group than in the control group (443 ± 30.0 ms versus 408 ± 28.0 ms, respectively, P < 0.0001) and more patients in the treatment group had a QTc interval greater than 450 ms (36.7% versus 7.5%, respectively, P = 0.0005). The QTc interval was not associated with methadone dose P = 0.9278), serum level (P = 0.2256) or duration of treatment (P = 0.1822).

Conclusions

This study has shown that methadone use is associated with longer QTc intervals, even among patients with daily doses of less than 80 mg. In this study, no correlation was found between QTc duration and methadone dose, serum levels or duration of use. However, the magnitude of the QTc interval was associated with female gender and the use of antidepressants.

Pharmacotherapy in the treatment of addiction: methadone

Methadone maintenance treatment (MMT) is the most widely available pharmacotherapy for opioid addiction and has been shown to be an effective and safe treatment over a period of 40 years. Although women comprise approximately 40% of clients currently being treated in MMT programs, comparatively little research geared specifically toward this group has been published. This article begins with an overview of neurobiological studies on opioid addiction, including a discussion of gender differences, followed by a review of the pharmacology of methadone. The authors then examine the particular needs and differences of women being treated in MMTs, including co-dependence with other substances, women's health issues, and psychosocial needs unique to this population. Research shows that women have different substance abuse treatment needs in comparison to their male counterparts. One New York City MMT program that has attempted to address these differences is highlighted.

Methadone initiation and rotation in the outpatient setting for patients with cancer pain

BACKGROUND

Methadone is an effective and inexpensive opioid for cancer pain treatment. It has been reported as difficult to use in the outpatient setting because of its variable relative potency and long half-life. The purpose of this study was to determine the outcome of methadone initiation or rotation for cancer pain treatment in outpatient settings.

METHODS

Chart review was done of 189 consecutive patients who underwent methadone initiation or rotation at the authors' palliative care outpatient center. Data were collected regarding demographic and clinical characteristics, symptoms, and opioid side effects at baseline and for 2 follow-up visits (F1, F2). Failure was defined as methadone discontinuation by the palliative care physician or patient's hospitalization for uncontrolled pain or methadone-related side effects at F1.

RESULTS

One hundred (53%) initiations and 89 (47%) rotations were conducted. Success rates for methadone initiation and rotation were 82 of 89 (92%) and 85 of 100 (84%), respectively. Mean (standard deviation) age was 60 (11) years. One hundred (53%) patients were women, 138 (73%) were white, and 182 (96%) had solid cancers. The main reason for rotation was pain (65 of 89 patients, 47%). Median (interquartile range, IQR) pain scores (Edmonton Symptom Assessment Scale/0-10) were 6 (5-8), 4 (3-6), and 3 (2-5) at baseline, F1, and F2, respectively (P < .0001). Median (IQR) daily methadone dose for initiation and rotation was 10 (5-15) mg and 15 (10-30) mg at F1 (P < .0001) and 10 (8-15) mg and 18 (10-30) mg at F2 (P < .0001), respectively. Constipation and nausea improved (P < .005) after initiation/rotation to methadone. Frequency of sedation, hallucinations, myoclonus, and delirium did not increase after initiation/rotation to methadone.

CONCLUSIONS

Outpatient methadone initiation and rotation for cancer pain treatment were safe, with high success rates and low side effect profiles.

Are opioid dependence and methadone maintenance treatment (MMT) documented in the medical record? A patient safety issue

BACKGROUND

Opioid-dependent patients often have co-occurring chronic illnesses requiring medications that interact with methadone. Methadone maintenance treatment (MMT) is typically provided separately from medical care. Hence, coordination of medical care and substance use treatment is important to preserve patient safety.

OBJECTIVE

To identify potential safety risks among MMT patients engaged in medical care by evaluating the frequency that opioid dependence and MMT documentation are missing in medical records and characterizing potential medication-methadone interactions.

METHODS

Among patients from a methadone clinic who received primary care from an affiliated, but separate, medical center, we reviewed electronic medical records for documentation of methadone, opioid dependence, and potential drug-methadone interactions. The proportions of medical records without opioid dependence and methadone documentation were estimated and potential medication-methadone interactions were identified.

RESULTS

Among the study subjects (n = 84), opioid dependence documentation was missing from the medical record in 30% (95% CI, 20%-41%) and MMT documentation was missing from either the last primary care note or the last hospital discharge summary in 11% (95% CI, 5%-19%). Sixty-nine percent of the study subjects had at least 1 medication that potentially interacted with methadone; 19% had 3 or more potentially interacting medications.

CONCLUSION

Among patients receiving MMT and medical care at different sites, documentation of opioid dependence and MMT in the medical record occurs for the majority, but is missing in a substantial number of patients. Most of these patients are prescribed medications that potentially interact with methadone. This study highlights opportunities for improved coordination between medical care and MMT.