Long-term antipsychotic use, orthostatic hypotension and falls in older adults with Alzheimer’s disease

Purpose: Antipsychotic use in Alzheimer disease (AD) is associated with adverse events and mortality. Whilst postulated to cause/exacerbate orthostatic hypotension (OH), the exact relationship between antipsychotic use and OH has never been explored in AD—a group who are particularly vulnerable to neuro-cardiovascular instability and adverse effects of medication on orthostatic blood pressure (BP) behaviour. Methods: We analysed longitudinal data from an 18-month trial of Nilvadipine in mild–moderate AD. We assessed the effect of long-term antipsychotic use (for the entire 18-month study duration) on orthostatic BP phenotypes measured on eight occasions, in addition to the relationship between antipsychotic use, BP phenotypes and incident falls. Results: Of 509 older adults with AD (aged 72.9 ± 8.3 years, 61.9% female), 10.6% (n = 54) were prescribed a long-term antipsychotic. Over 18 months, long-term antipsychotic use was associated with a greater likelihood of experiencing sit-to-stand OH (ssOH) (OR: 1.21; 1.05–1.38, p = 0.009) which persisted on covariate adjustment. Following adjustment for important clinical confounders, both antipsychotic use (IRR: 1.80, 1.11–2.92, p = 0.018) and ssOH (IRR: 1.44, 1.00–2.06, p = 0.048) were associated with a greater risk of falls/syncope over 18 months in older adults with mild–moderate AD. Conclusion: Even in mild-to-moderate AD, long-term antipsychotic use was associated with ssOH. Both antipsychotic use and ssOH were associated with a greater risk of incident falls/syncope over 18 months. Further attention to optimal prescribing interventions in this cohort is warranted and may involve screening older adults with AD prescribed antipsychotics for both orthostatic symptoms and falls.