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.