Abstract
OBJECTIVE: Methadone treatment is effective for managing opioid use disorder (OUD) but raises concerns about its impact on cardiac function. This study aimed to assess the prevalence of cardiac dysfunction among individuals under methadone treatment. METHODS: This cross-sectional study involved 200 OUD patients admitted to addiction treatment centers of Kerman, Iran, who were at least 1 year under methadone maintenance therapy. Participants were enrolled using a convenience sampling method. Exclusion criteria included concurrent alcohol or nonopioid drug abuse, underlying diseases affecting cardiac function (diabetes, hypertension, and chronic renal failure), hepatic diseases, or use of drugs affecting methadone metabolism. Data on methadone dose, treatment duration, and cardiac parameters assessed through echocardiography and electrocardiography were collected. FINDINGS: A total of 200 OUD patients aged 46.34 ± 13.93 years (72% male) were included. The average duration of methadone use was 2.17 ± 1.34 years, and the average dose was 52.10 ± 27.46 mg/day. 38% of subjects had QT prolongation, while echocardiographic assessment revealed various cardiac abnormalities: 17.5% with systolic dysfunction, 12.5% with abnormal left ventricular end-diastolic diameter, 66.5% with diastolic dysfunction, and 15.5% with increased systolic pulmonary artery pressure. Significant correlations were observed between methadone dose and duration with all measured cardiac parameters. CONCLUSION: This study demonstrated an association between methadone treatment characteristics (higher dose and longer duration) and cardiac dysfunction. These findings suggest dose- and time-dependent cardiotoxic effects of methadone. Clinicians should implement cardiac monitoring, dose minimization, and risk-reduction strategies for patients on long-term methadone therapy.