UBC Theses and Dissertations
Methadone dosing in Vancouver, British Columbia : the distribution of prescribed doses, predictors of dose and dose-associated behaviours Piaseczna, Magdalena Anna
Objectives: The primary objectives of this study are to describe the methadone doses that are being prescribed in a large population of injection drug users in Vancouver, British Columbia, to determine whether methadone dose adequacy, along with other factors, are associated with prescribing certain methadone doses and to determine whether patient perception of dose adequacy is associated with the presence of HIV-risk behaviours over time. This thesis also aims to provide a deeper understanding of methadone treatment programs in British Columbia and suggest ways in which methadone maintenance treatment programs can be improved. Methods: The Vancouver Injection Drug Users Study follows injection drug users in British Columbia's Lower Mainland through semi-annual interviewer-administered questionnaires. Interviewers gather detailed information, including data regarding participants' age, gender, HIV status, injection and drug-using behaviour, treatment program utilization. Linear, logistic and generalized estimating equation analyses were performed to address the objectives above. Results: The median methadone dose was approximately 100 mg per day. Patient perspective of dose adequacy was significantly associated with the dose that patients were prescribed, with persons who reported too low a dose receiving the highest doses and those who reported that their dose was high received the lowest methadone doses. Subsequent analyses demonstrated that patients' perspectives of dose adequacy were associated with prevalence of specific HIV risk behaviours such as condom use heroin injection. Conclusion: Methadone doses in the Lower Mainland are high compared to the majority of reports in the literature around the world. Patient satisfaction with dose is highly associated with prescribed methadone dose, which in turn strongly associated with HIV risk behaviours over time. Methadone providers need to work with patients to ensure patient satisfaction with methadone treatment to positively influence methadone treatment outcomes.
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