Use of Therapeutic Drug Monitoring to Characterize Cefepime-Induced Neurotoxicity

BackgroundThe incidence of cefepime-induced neurotoxicity (CIN) in hospitalized patients is highly variable. Although greater cefepime exposures incite neurotoxicity, data evaluating trough thresholds associated with CIN remains limited. The objectives of this study were to evaluate the incidence of CIN, assess the relationship between cefepime trough concentrations and CIN, investigate clinical factors associated with CIN, and describe electroencephalogram (EEG) abnormalities in CIN. MethodsThis was a retrospective study of adult patients who had received [≥] 5 days of cefepime with [≥] 1 trough concentration > 25 mg/L. Potential CIN cases were identified utilizing neurological symptoms, neurologist assessments, EEG findings and improvement of neurotoxicity after cefepime discontinuation. ResultsOne-hundred and forty-two patients were included. The incidence of CIN was 13% (18/142). The mean cefepime trough concentration in CIN patients was significantly greater than the non-neurotoxicity group (74.2 mg/L {+/-} 41.1 vs. 46.6 mg/L {+/-} 23, p=0.015). Lower renal function (creatinine clearance < 30 ml/min), greater time to therapeutic drug monitoring (TDM) ([≥]72 hours), and each 1 mg/mL rise in cefepime trough were independently associated with increased risk of CIN. Moderate generalized slowing of the background rhythm was the most common EEG pattern associated with CIN. ConclusionCefepime should be used cautiously in hospitalized patients due to the risk of neurotoxicity. Patients with greater renal function and those who had early cefepime TDM ([≤] 72 hours) had lower risk of CIN.