What's behind delirium: is there a specific role for medications?

Purpose: Delirium in nursing home (NH) residents is typically multifactorial and complex. This narrative review aims to synthesize the current literature on medications that are identified as predisposing and precipitating factors for delirium in older adults in NHs.

Methods: A comprehensive PubMed search was carried out to identify English-language publications up to March 2025. Studies were included if they explored the role of medications in inducing delirium in NH residents aged 65 years and older.

Results: While there is substantial evidence linking medications to delirium, the number of studies evaluating their effects in the NH setting is notably limited. Several studies conducted in NHs confirmed the association between anticholinergic drugs and delirium. Antipsychotic medications and benzodiazepines may increase the risk of delirium onset. However, the studies conducted in NHs are insufficient to make definitive recommendations due to the small sample sizes and conflicting results. Other classes of medications have been recognized as potential delirium triggers in other healthcare settings, but existing evidence in NHs is either limited or absent.

Conclusion: Determining which medications that trigger delirium is complicated by the presence of numerous confounding factors among NH residents, including cognitive impairment, frailty, multimorbidity, polypharmacy, acute medical conditions, pain, end-of-life care, and organizational factors that can interact and amplify the risk. More research is necessary to establish the role of medications in the etiology of delirium in this population.