Analysis of Concomitant Medications Prescribed with Antipsychotics to Patients with Dementia

INTRODUCTION: Antipsychotics are still commonly prescribed to patients with dementia, despite the many issues that have been identified. This study aimed to quantify antipsychotic prescription in patients with dementia and the types of concomitant medications prescribed with antipsychotics. METHODS: A total of 1,512 outpatients with dementia who visited our department between April 1, 2013 and March 31, 2021, were included in this study. Demographic data, dementia subtypes, and regular medication use at the time of the first outpatient visit were investigated. The association between antipsychotic prescriptions and referral sources, dementia subtypes, antidementia drug use, polypharmacy, and prescription of potentially inappropriate medications (PIMs) was evaluated. RESULTS: The antipsychotic prescription rate for patients with dementia was 11.5%. In a comparison of dementia subtypes, the antipsychotic prescription rate was significantly higher for patients with dementia with Lewy bodies (DLB) than for those with all other dementia subtypes. In terms of concomitant medications, patients taking antidementia drugs, polypharmacy, and PIMs were more likely to receive antipsychotic prescriptions than those who were not taking these medications. Multivariate logistic regression analysis showed that referrals from psychiatric institutions, DLB, N-methyl-d-aspartate (NMDA) receptor antagonists, polypharmacy, and benzodiazepine were associated with antipsychotic prescriptions. CONCLUSIONS: Referrals from psychiatric institutions, DLB, NMDA receptor antagonist, polypharmacy, and benzodiazepine were associated with antipsychotic prescriptions for patients with dementia. To optimise prescription of antipsychotics, it is necessary to improve cooperation between local and specialised medical institutions for accurate diagnosis, evaluate the effects of concomitant medication administration, and solve the prescribing cascade.