Evaluation of QTc interval in Iranian causalities (Janbazan) of Iran-Iraq war receiving maintenance methadone treatment

BACKGROUND Methadone is a synthetic opioid, used in treatment of chronic pains. The current study was carried out to evaluate the QTc interval in Iranian causalities (Janbazan) of Iran-Iraq war receiving maintenance methadone treatment. MATERIALS AND METHODS In 2010, one hundred war causalities in Isfahan who chronically take daily dose of 20 mg or more of methadone (more than 2 weeks), and did not have the history of cerebrovascular or coronary artery diseases, cardiac pacemaker, congenital prolonged QTC, or taking drugs affecting QTc, or having electrolyte abnormalities, were selected for the study. An electrocardiogram was taken from each patient using cardiofax instrument, and QTC was calculated manually. The data was analyzed using SPSS software with descriptive statistical methods and Pearson's correlation coefficient. FINDINGS All patients were male and had the mean age of 45.6 ± 6.1 years. The patients received 20-240 mg methadone daily for 1 to 108 months. The QTc was prolonged in 25% of the patients (QTc 5 450 ms), with the mean of 472.72 ± 18.5 ms (range 450-508 ms) and the mean daily dose of methadone 85.2 ± 59.0 mg. No significant relationship was observed between QTC interval on the one hand, and methadone dose (R = 0.025, P = 0.8), duration of treatment (R =-0.048, P = 0.68), age (R = 0.037, P = 0.71), and weight (R = 0.1, P = 0.21) of the patients, on the other hand. None of the patients had faint, syncope, arrhythmia, or sudden death. CONCLUSION Oral methadone causes prolongation of QTC interval. However, the dosage of methadone and duration of treatment were not statistically related to QTC interval.