We analyzed the impact of opioid initiation on the prevalence of antipsychotic and benzodiazepine and related drug (BZDR) use among community-dwelling persons with Alzheimer's disease (AD).

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.