Safety assessment of low doses of methadone in combination with benzodiazepines in real occasions during methadone maintenance treatment - a pilot study

Abstract

Background. Methadone is a synthetic opioid used for methadone maintenance treatment (MMT) in patients with heroin addiction. However, at therapeutic levels methadone may be related to QT prolongation on the electrocardiogram (ECG), which might induce torsades de pointes. Aim. Our study assessed the safety of low methadone doses in combination with benzodiazepines in opiate addicts in MMT after ascertaining differences in corrected QT (QTc) intervals and side-effects. Materials and Methods The study included 20 opiate addicts who were referred to the MMT at the Department of Psychiatry, Clinical Centre of Vojvodina, in 2012. Before the beginning of the investigation, all patients underwent an ECG, and data were collected on their sociodemographic status, duration of heroin abuse period, other drugs used in combination with heroin and the presence of ECG disorders. One month after the beginning of MMT, the patients were interviewed about their general condition during the MMT and about the side-effects they had experienced, after which an ECG was performed. Data about the methadone dose applied and the use of other drugs were collected from the medical history of each patient. Results. A significant increase in the length of QTc intervals after one month of MMT compared with those at the baseline was observed. A dose-dependent correlation between the daily dose of diazepam, used in combination with methadone, and QTc was noted. None of the participants experienced any cardiac side-effects. Conclusions. On the basis of our results, it appears to be advisable to perform a pre-treatment ECG and then regular ECG check-ups after one month of MMT, especially in the case of a concomitant use of benzodiazepines.