Antimicrobial-induced cognitive side effects

INTRODUCTION: Antimicrobial-induced cognitive side effects are often overlooked or underreported. Literature often reports symptoms of antimicrobial-induced cognitive impairment under more general blanket terms, such as neuropsychiatric side effects, neurotoxicity, or drug-induced delirium or encephalopathy. METHODS: A PubMed search using terms including antibiotics, antifungals, antivirals, antimalarials, side effects, cognitive, neurotoxicity, encephalopathy, and delirium was conducted. Respectively, symptoms of cognitive impairment were teased out of the multiple neurologic complications presented for each case and reported based on antimicrobial class. Articles were excluded if they focused solely on neuropsychiatric side effects such as seizures, psychosis, hallucinations, or mood disturbances, were conducted in animals, or involved antiretroviral medication therapies. RESULTS: Of over 50 case reviews, case reports, retrospective chart reviews, and prospective cohort studies analyzed, 25 were deemed appropriate for purposes of this review. Common antimicrobial-induced cognitive side effects for all antimicrobial classes included confusion, delirium, encephalopathy, and impaired concentration or attention. Recurring risk factors included, but were not limited to, older age and renal impairment. Mechanisms of cognitive impairment were relatively specific to each antimicrobial class. DISCUSSION: Awareness of the potential for antimicrobial-induced cognitive side effects, including the general time frame of symptom onset and symptom presentation, is critical in challenging patient cases. This review article aims to summarize the risk factors, clinical symptoms, mechanisms, and management of antimicrobial-induced cognitive side effects. Pharmacists can play a key role in prevention through adjustment of medications for renal or hepatic dysfunction, avoidance of polypharmacy, and knowledge of critical drug interactions that may precipitate cognitive decline.