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

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. 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 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. 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. 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.