Seizures Associated With High-Dose Cefazolin in a Patient With Renal Dysfunction: A Case Report.

Introduction and Objective: Cefazolin-induced encephalopathy and seizures are possibly related to excessive dosing; especially in those with renal dysfunction. This report aims to highlight the importance of dose adjustments of cefazolin in patients with diminished renal function. Case Presentation: An 87-year-old female with a history of cognitive impairment, remote cerebellar infarcts, hypertension, and hypothyroidism presented with acute delirium associated with a urinary tract infection. Her condition worsened and she was found to have a methicillin-sensitive Staphylococcus aureus bacteremia for which she was started on cefazolin 2 grams intravenously every 4 hours. Based on her renal function, recommended dosing would have been 2 grams intravenously every 12 hours. After 3 days on this regimen her mentation declined and she suffered a tonic-clonic seizure. She did not regain consciousness and was transitioned to comfort care prior to her death. Discussion: Supratherapeutic dosing of cefazolin may have led to significant neurotoxic effects. Neurotoxicity and seizures can occur with drug accumulation from an increase in excitatory neurotransmitters along with a decrease in inhibitory neurotransmitter activity. The effect is potentiated by older age, pre-existing central nervous system conditions, and renal failure. Therapeutic drug monitoring is a potential strategy to limit the risk of drug toxicity. Conclusion: This case outlines a poor outcome in the context of high-dose cefazolin. It serves as a reminder to clinicians for ongoing pharmacovigilance in adhering to treatment guidelines.