METHODS: Clinical records of active opioid dependents who underwent MMT between 1 January 2007 and 31 March 2021 in Hospital Tuanku Fauziah, Perlis, Malaysia were retrospectively reviewed. Data collected included baseline demographics, history of illicit drug use, temporal trend in methadone dosage modulation, and co-use of illicit drugs during the MMT.

RESULTS: A total of 87 patients (mean age, 43.9 ± 8.33 years) were included. Their mean duration of involvement in MMT was 7.8 ± 3.69 years. The most commonly used drug was heroin (88.5%), followed by kratom (51.7%). Between 2019 and 2021, 61 (70.1%) patients had ceased abusing opioid, but 51 (58.6%) patients continued using any of the illicit drugs. Methamphetamine and amphetamine co-use was most common (n = 12, 37.5%). Hepatitis C status was not associated with the current methadone dose (U = 539.5, p = 0.186) or the highest dose required (t = -0.291, df = 74, p = 0.772). No predictor for illicit drug abstinence during MMT was identified. Methadone dose positively correlated with frequency of defaulting treatments (r = 0.22, p = 0.042).