Impact of opioid initiation on antipsychotic and benzodiazepine and related drug use among persons with Alzheimer's disease.

Abstract

We utilized the register-based Medication use and Alzheimer's disease (MEDALZ) cohort for this study. We included all community-dwelling persons diagnosed with AD during 2010-2011 in Finland initiating opioid use (n = 3,327) and a matched cohort of persons not initiating opioids (n = 3,325). Interrupted time series analyses were conducted to compare the prevalence of antipsychotic and BZDR use in 30-day periods within six months before opioid initiation to 30-day periods six months later. Before opioid initiation, prevalence of antipsychotic use among opioid initiators was 13.3%, 18.3% at opioid initiation, and 17.3% six months later. Prevalences of BZDR use were 27.1% six months prior, 28.9% at opioid initiation, and 26.9% six months later. After opioid initiation, antipsychotic and BZDR use declined by 0.3 percentage points (pps, 95% confidence interval 0.1-0.5) and 0.4 pps (0.2-0.7) per month, respectively, until the end of the follow-up. Compared to persons not initiating opioid use, opioid initiation immediately resulted in an increase in prevalence of 1.9 pps (0.9-2.8) for antipsychotics and of 1.6 pps (0.9-2.2) for BZDR use. However, in total there was a comparative decrease of 0.5 pps (0.3-0.8) per month for antipsychotics and of 0.4 pps (0.2-0.6) for BZDR use until the end of the follow-up. Our results suggest that opioid initiation may reduce antipsychotic and BZDR use among persons with AD.