Switching pharmacies leads to gaps in medication possession in individuals treated with buprenorphine.

Abstract Background Not all pharmacies stock and dispense buprenorphine potentially complicating continuous access to care for patients with opioid use disorder. This may become problematic if a patient’s primary pharmacy can no longer provide buprenorphine and the patient cannot locate a new pharmacy. Objective To identify how often patients treated with buprenorphine for OUD switch pharmacies and to estimate the association between switching pharmacies and a clinically significant gap in therapy of seven-days or longer. Methods A retrospective, repeated measures, longitudinal cohort design was used. Patients initiating treatment with a buprenorphine product indicated for opioid use disorder were identified from the 2016-2018 Texas Prescription Monitoring Program. The predictor of interest, switching pharmacies, was defined by comparing the dispensary used between subsequent prescriptions. The outcome of interest was defined as a gap in medication possession of seven-days or longer based on the National Quality Forum’s definition of continuity of pharmacotherapy for opioid use disorder. A general estimating equation approach was used to estimate a repeated measures logistic regression measuring the association between switching pharmacies and a gap in therapy. Results Of 13,375 eligible patients, 29.6% switched pharmacies at least once during treatment and 51.6% of those did so more than once. The median time to initial switch was 30 (IQR:13-66) days. When patients switched pharmacies, they were significantly more likely to have a gap in therapy between 7 and 29 days (aOR: 1.67, 95% CI: 1.57-1.78). Conclusion Patients receiving buprenorphine switch pharmacies early and frequently in treatment which leads to clinically significant gaps in therapy. While qualitative explanatory work is needed to understand why patients switch pharmacies so often, pharmacists and prescribers must ensure that patients have reliable access to a convenient source of buprenorphine to prevent gaps in therapy.