Identification and Management of In-Hospital Drug-Induced Delirium in Older Patients

Angela G. Catic

Delirium, an acute confusional state with changes in attention and cognition, is a common cause of morbidity and mortality among hospitalized elders. Medications are responsible for up to 39% of delirium cases in the elderly. The incidence of drug-induced delirium is particularly high in this population due to the altered pharmacokinetics and pharmacodynamics of aging, high prevalence of polypharmacy and occurrence of co-morbid disease. Although certain medications are more often associated with the development of delirium, including opioids, benzodiazepines, anticholinergics and antidepressants, any medication can cause delirium in the elderly. Evaluation of delirium should include a thorough medication history, which should determine if any new medications have been initiated, if medications have been discontinued, and the details of any recent dosage adjustments. It is important to understand the utility of medications in preventing and treating delirium in the elderly. Acetylcholinesterase inhibitors have not been found to reduce the incidence of delirium or length of hospitalization. Study results regarding the utility of antipsychotic medications in preventing delirium have been mixed. Haloperidol prophylaxis did not reduce the occurrence of delirium, but it did reduce the severity and duration. Olanzapine and risperidone were associated with a reduced incidence of delirium compared with placebo. Pharmacological therapy to treat delirium should be implemented only if patients pose a safety risk to themselves or others. Typical and atypical antipsychotics are effective in treating the symptoms of delirium, but it is important to note that they are not approved by the US FDA for this indication. Short-acting benzodiazepines are second-line therapy and are typically reserved for patients with sedative/alcohol withdrawal, Parkinson's disease or neuroleptic malignant syndrome. Study results regarding the utility of acetylcholinesterase inhibitors have been mixed.