Changes in pharmacy are associated with gaps in medication possession in individuals treated with buprenorphine

Abstract

Objective: The objective of this study was to identify the prevalence of changes in pharmacy among incident buprenorphine users and to estimate the association between a change in pharmacy and a clinically significant gap in therapy of seven-days or longer. Methods: A repeated measures, cohort design was used to assess the association between changes in pharmacy and 7-day gaps in therapy. We first identified a cohort of patients with incident buprenorphine use from the Texas Prescription Monitoring Program. We then excluded those who filled less than three-prescriptions or completed less than seven-days of pharmacotherapy. From there, we lagged each patient’s previous pharmacy forward to determine if they changed pharmacies between subsequent prescription fills. A random intercept, fixed slope mixed model with a logistic link was then used to measure the association between a change in pharmacy and a gap in therapy. Results: Of 13,189 eligible patients, 29.5% had at least one change in pharmacy and 51.5% of those did so more than once. The median time to initial change in pharmacy was 30 (IQR:13-75) days. Patients who changed pharmacies were significantly more likely to have a gap in therapy between 7 and 29 days (aOR:1.96, 95% CI=1.81-2.13).Conclusion: Patients receiving buprenorphine based MOUD change pharmacies frequently and early in treatment which leads to clinically gaps in therapy. While qualitative explanatory work is needed to understand the reasons for such frequent changes in pharmacy, pharmacists and prescribers must both work to ensure that patients have reliable access to a convenient and reliable source of buprenorphine in order to prevent changes in pharmacy.