Theme: Epidemiology & Public Health Research Year: 2025
Background:
In 2022, South Africa introduced a 10 mg/ml methadone formulation, differing in strength from the original 2 mg/ml version. Formulation changes may lead to adverse effects, impacting treatment outcomes for people on opioid agonist therapy (OAT). This study evaluated the adverse effects, withdrawal symptoms, cravings, and dosing of clients transitioning from a 2mg/ml to 10mg/ml methadone formulation.
Methods:
A cross-sectional study with pre- and post-transition assessments was conducted between November 2022 and July 2023 across 12 Community Oriented Substance Use Programme (COSUP) sites in Tshwane, South Africa. Participants were selected through convenience sampling and had to be stabilized on the 2 mg/ml formulation before transitioning. Data were collected using a paper-based survey, assessing participants’ experiences with methadone before and one month after switching formulations. Descriptive statistics, including median age and frequency distributions, were used for analysis.
Results:
A total of the 56 participants met the eligibility criteria, with the majority identified as male (n=47, 85.5%). The median age was 37 (IQR 33-42) and more than half (n=33, 59%) self-reported as noninjecting opioid users. After the transition, there was less constipation, sleep issues, and hallucinations, but nausea, dizziness, and vertigo increased. Weight gain and sweat remained unchanged. More participants on the 10 mg/ml formulation (n=34, 60.7%) reported no cravings compared to those on the 2 mg/ml formulation (n=31, 55.4%).
Conclusion:
This study highlights the varied experiences of individuals transitioning to the 10 mg/ml methadone formulation in Tshwane, South Africa. While side effects varied, cravings decreased among participants using the higher (10 mg/ml) formulation. This potentially supports treatment adherence and long-term recovery. These findings emphasize the importance of continuously monitoring individual responses to formulation changes and tailoring opioid agonist therapy (OAT) to optimize patient outcomes.
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