DOI: https://doi.org/10.36347/sjmcr.2026.v14i09.011

Pages: 891-895

Objective: To evaluate the side effects of methadone in patients undergoing Opioid Agonist Therapy (OAT) and to determine their impact on treatment adherence. Methods: A prospective descriptive study conducted among a sample of 67 patients enrolled in the Methadone Program at the Ar-razi University Psychiatric Hospital in Salé (Morocco). Inclusion criteria were: age ≥ 18 years, a diagnosis of opioid use disorder according to the DSM-5 TR, and treatment with methadone for at least 3 months. Data were collected through medical consultations and a pre-designed questionnaire, then analyzed using Microsoft Excel. Results: The sample was predominantly male (79.1%), aged 31 to 40 years (61.2%), single (47.8%), of average socioeconomic status (50.7%), unemployed (49.3%), and 44.8% had a criminal history. Prior to enrollment, heroin was the most commonly used substance (68.7%), primarily smoked (64.2%). The most common side effects were constipation (70.1%), excessive sweating (68.7%), drowsiness and nausea/vomiting (40.3% each), erectile dysfunction (20.9% of all patients, all cases in men), and amenorrhea (10.4% of all patients, all cases in women). These effects were most pronounced at the start of treatment (55%). Only 13% of patients felt that these effects had influenced their adherence to treatment; 78% reported an improvement in their quality of life while on methadone. Conclusion: Methadone, like most opioids, is not without adverse effects that could potentially impact treatment adherence. However, these effects compromised adherence in only a minority of patients, while the majority experienced a marked improvement in their quality of life. Appropriate care and close monitoring, particularly at the start of treatment, remain essential to minimize these effects and optimize treatment adherence.