Defining dosing pattern characteristics of successful tapers following methadone maintenance treatment: results from a population-based retrospective cohort study.

AIMS To identify dose-tapering strategies associated with sustained success following methadone maintenance treatment (MMT). DESIGN Population-based retrospective cohort study. SETTING Linked administrative medication dispensation data from British Columbia, Canada. PARTICIPANTS From 25 545 completed MMT episodes, 14 602 of which initiated a taper, 4183 individuals (accounting for 4917 MMT episodes) from 1996 to 2006 met study inclusion criteria. MEASUREMENTS The primary outcome was sustained successful taper, defined as a daily dose ≤5 mg per day in the final week of the treatment episode and no treatment re-entry, opioid-related hospitalization or mortality within 18 months following episode completion. FINDINGS The overall rate of sustained success was 13% among episodes meeting inclusion criteria (646 of 4917), 4.4% (646 of 14 602) among all episodes initiating a taper and 2.5% (646 of 25 545) among all completed episodes in the data set. The results of our multivariate logistic regression analyses suggested that longer tapers had substantially higher odds of success [12-52 weeks versus <12 weeks: odds ratio (OR): 3.58; 95% confidence interval (CI): 2.76-4.65; >52 weeks versus <12 weeks: OR: 6.68; 95% CI: 5.13-8.70], regardless of how early in the treatment episode the taper was initiated, and a more gradual, stepped tapering schedule, with dose decreases scheduled in only 25-50% of the weeks of the taper, provided the highest odds of sustained success (versus <25%: OR: 1.61; 95% CI: 1.22-2.14). CONCLUSIONS The majority of patients attempting to taper from methadone maintenance treatment will not succeed. Success is enhanced by gradual dose reductions interspersed with periods of stabilization. These results can inform the development of a more refined guideline for future clinical practice.