Administration matters! A retrospective cohort study of medication dispensing at pharmacies
Background: Opioid agonist treatment for opioid use disorders may be delivered at treatment clinics or dispensed from pharmacies, however the type of delivery may be associated with risks. The aim of the study was to investigate whether dispensing of methadone or buprenorphine at pharmacies during treatment for opioid use disorders was associated with adverse outcomes.
Methods:Retrospective cohort study using a national, linked, population-level data set from Denmark. Patients included were between 18 and 75 years, living in Denmark, and admitted for treatment for opioid use disorders during 2000-2016 (n=9,299). Cox proportional hazards regression was estimated for convictions, non-fatal overdoses, and death, after the first dispensing of either methadone or buprenorphine from a pharmacy after starting treatment.
Results: Of all patients, 68% had methadone and 31% had buprenorphine dispensed at a pharmacy. Compared with the time prior to pharmacy dispension, the risk of criminal convictions increased after having methadone dispensed from a pharmacy (adjusted hazard ratio (aHR) = 1.25, 95% confidence interval (CI) = 1.19-1.31), all-cause mortality (aHR = 1.54, CI = 1.41-1.68), and non-fatal overdoses (aHR = 1.50, CI 1.56-1.86). After having buprenorphine dispensed at a pharmacy, risk of criminal convictions increased (aHR = 1.12, CI = 1.01-1.17) and non-fatal overdoses (aHR = 1.44, CI = 1.31-1.58), but not all-cause mortality (aHR = 1.06, CI = 0.97-1.16).
Conclusion: Opioid agonist treatment may often require more clinical follow-up than what is typically provided when medication is dispensed at pharmacies.