Concomitant Drug Use in Patients on Methadone Maintenance Therapy

Methadone maintenance therapy (MMT) is considered as an efficient and effective treatment in management of high risk opioids addiction; although, concomitant use of other drugs may interfere with treatment course and outcome in MMT cases. This study aimed at evaluating patterns of drug use along with methadone based on self reported and urine analysis data in two MMT clinics.
135 patients on MMT recruited for this cross-sectional study which was conducted from March to September 2014. Data were obtained of MMT clinic of Imam Reza (p) hospital, Mashhad, Iran. After completing a written informed consent, a questionnaire including demographic information, duration of MMT, methadone dose, concomitant medication and other related information was fulfilled. Data were analyzed by SPSS software version 16.
Mean (SD) age of patients was 42.8 (12.2). All patients were taking medication along with methadone. The most prevalent drug classes were antidepressants (32%) and benzodiazepines (BNZD) (25%). The next three drug groups were analgesics, GI and cardiovascular drugs respectively. Antidepressant and benzodiazepine use was more prevalent in patients who were on MMT for at least 7 months compared with shorter courses. Antidepressant use was more common in patients on maximum dose of 30 mg/day methadone while BNZD use was more frequent in patients on doses higher than 30 mg/d.
Psychiatric drug use is common in opioid addicted cases. BNZD and antidepressant drugs were two most consumed drugs in cases on MMT based on our study. Psychiatric drug consumption was more common in patients on higher length of methadone use. Dosage of methadone may affect kind of concomitant drug use. Physicians should be aware of interactions between psychiatric medications and opioids.