Methadone Maintenance and QT-Interval: Prevalence and Risk Factors-Is It Effective to Switch Therapy to Levomethadone?

Methadone is a chiral synthetic opioid primarily used to treat heroin and prescriptionopioid addiction: the (R)-enantiomer (Levomethadone) activates the mu-opioid receptor more potently than the (S)-enantiomer, which is a more potent blocker of the hERG potassium channels, resulting in QTc prolongation. The purpose of this retrospective study was to assess the effect of methadone on the QTc interval and to investigate the benefits of Levomethadone. The electrocardiograms of 165 patients taking methadone at various dosages and for different periods of time were examined: the QTc value was manually measured and then adjusted using Bazett's formula. Data analysis revealed a linear association between the dosage of methadone and QTc length; no correlation was found between the QTc value and gender, age, or duration of therapy. In total, 14% of the sample (23 patients) showed a prolongation of the QTc interval (>470 ms in males and >480 ms in females); 10 of the 23 patients with QTc elongation underwent a change of therapy from Methadone to Levomethadone-in 90% of these patients, a normalization in the QTc length was established. This study confirmed the role of methadone, specifically its dosage, in QTc prolongation and the efficiency of Levomethadone as an adequate therapeutic substitute in these circumstances. This study validates the importance of careful electrocardiographic monitoring in methadone-treated patients.

Automated summary

This study assessed the effect of methadone on the QTc interval and investigated the benefits of Levomethadone. Results showed a linear association between methadone dosage and QTc length, and no correlation between QTc value and gender, age, or therapy duration. The study confirmed the role of methadone in QTc prolongation and validated the efficiency of Levomethadone as a therapeutic substitute, highlighting the importance of electrocardiographic monitoring in methadone-treated patients.