Update on Pharmacotherapy for Prevention and Treatment of Post-operative Delirium: A Systematic Evidence Review

Delirium is highly prevalent among elderly post-operative patients with no pharmacological intervention approved by the Food and Drug Administration for prevention or treatment. We conducted a systematic evidence review to critically appraise literature related to the pharmacotherapy of post-operative delirium. Ten studies fulfilled our inclusion criteria with two interventions for delirium treatment and eight interventions for delirium prevention in post-operative patients. The quality of evidence of delirium treatment studies was poor, whereas the quality of evidence in delirium prevention studies ranges from moderate to high. Delirium treatment studies find similar delirium duration and length-of-stay outcomes between haloperidol and either morphine or ondansetron. Risperidone was found to reduce the conversion of sub-syndromal delirium to delirium in one study compared to placebo. Haloperidol, olanzapine, and ketamine were each found to reduce delirium incidence, whereas rivastigmine had no impact on delirium incidence or duration. Lighter anesthesia as monitored by bi-spectral index led to a decreased delirium incidence. Considering results from studies conducted prior to the dates of this review, the current evidence suggests that certain pharmacologic classes and lighter sedation using BIS monitoring may prevent post-operative delirium, although a conclusive recommendation for clinical practice must await further research.