To address concerns regarding the intravenous diversion of buprenorphine, a combined buprenorphine-naloxone (BUP-NLX) preparation was developed. The aim of this study is to compare health outcomes in opioid dependent patients treated with BUP and BUP-NLX. All patients treated with BUP and/or BUP-NLX in Western Australia between 2001 and 2010 were included in the study ( N = 3455). Patients were identified via State prescribing records and matched against the State mortality, hospital, and emergency department records. Rates of health events were examined and compared using Cox Proportional Hazard Models and Generalized Estimating Equations. While on treatment there was no significant difference between mortality rates in the two groups, mortality rates following the cessation of treatment were significantly higher in patients treated with BUP-NLX (adjusted hazard ratio: 1.59). Rates of hospitalization were significantly elevated in BUP-NLX patients (adjusted odds ratio: 1.17) compared with BUP treated patients; however, rates of hospitalization with a skin/subcutaneous diagnosis were significantly lower in BUP-NLX treated patients (adjusted odds ratio: 0.65). Off-treatment rates of both all-cause hospital admissions (adjusted odds ratio: 1.53) and hospital admissions with an opioid poisoning diagnosis (adjusted odds ratio: 1.59) were significantly elevated in BUP-NLX treated patients compared with BUP treated patients. The addition of naloxone does not appear to improve the safety profile of buprenorphine.
Keywords: Buprenorphine; mortality; naloxone; safety.