AbstractBackground and AimsPotentially inappropriate medications (PIMs) carry risks that outweigh any potential benefits when compared to safer or more effective alternative treatments. Adverse drug events are more likely to occur in older adults with psychiatric diseases due to multimorbidity, polypharmacy, and age‐related changes in drug pharmacokinetics and pharmacodynamics. The aim of this study was to assess the prevalence and risk factors of PIM use in an aged care hospital's psychogeriatric division, using the American Geriatrics Society Beers criteria 2019.MethodsThis cross‐sectional study was conducted on all current inpatients, having a mental disorder and aged ≥65 years, in one elderly care hospital in Beirut, from March to May 2022. Medications, sociodemographic and clinical characteristics were collected from patients' medical records. PIMs were evaluated based on Beers criteria 2019. Independent variables were described using descriptive statistics. Factors associated with PIM use were identified by bivariate analysis followed by binary logistic regression. A two‐sidedpvalue <0.05 was considered statistically significant.ResultsThe study included 147 patients, with a mean age of 76.3 years, 46.9% of them having schizophrenia, 68.7% using 5 or more drugs and 90.5% taking at least 1 PIM. The most prescribed PIMs were antipsychotics (40.2%), anticholinergics (16%), and antidepressants (7.8%). PIM use was significantly associated with polypharmacy (AOR = 20.88, 95% CI: 1.22−357.87,p= 0.04) and anticholinergic cognitive burden (ACB) score (AOR = 7.25, 95% CI: 1.13−46.52,p= 0.04).ConclusionPIMs were highly prevalent among hospitalized Lebanese psychiatric elderly. Polypharmacy and ACB score were the determinants of PIM use. A multidisciplinary medication review led by a clinical pharmacist could reduce PIM use.