Introduction: Cefepime induced neurotoxicity (CIN) is commonly associated with renal dysfunction, however CIN can occur in patients with normal renal function or renally dose-adjusted regimens. Few reports of this kind have obtained cefepime concentrations to assist in diagnosis. Patient Case: A 42-year old female with a complex past medical history was transferred to our facility with chief complaint of worsening shock and respiratory failure, and the patient was also noted to be hypernatremic, experiencing diabetic ketoacidosis (DKA), and acute kidney injury (AKI). Her DKA resolved and hypernatremia and AKI began to improve. As a result, cefepime was dose-adjusted for renal function estimated by the Cockcroft-Gault (CG) equation. Her hospital course was complicated by persistent altered mental status (AMS), preventing extubation. Cefepime was discontinued due to concern for CIN, and a concentration was obtained 13-hours after the last dose which was elevated at 49 µg/mL. Two days following cefepime discontinuation, the patient’s mental status improved allowing for successful extubation. The patient remained stable and was discharged to an acute care floor and then ultimately back to home. Conclusion: CIN should be part of a wider differential diagnosis for patients experiencing encephalopathy, and inaccurate renal function estimation may be a risk factor for developing CIN. Furthermore, therapeutic drug monitoring (TDM) may serve as an important clinical tool in diagnosing and managing CIN.