Abstract
Case Report: We report a 20-year-old woman who developed altered mental status, massive crystalluria, and acute renal failure following an intentional overdose of felbamate and sodium valproate. Peak plasma concentrations of felbamate and sodium valproate were 200 μmg/mL and 470 μmg/mL, respectively. Macroscopic urinary crystals formed approximately 18 hours after ingestion and were identified by gas chromatography as containing felbamate. Renal ultrasound revealed unilateral hydronephrosis. Following parenteral hydration, the crystalluria and acute renal failure resolved and the patient recovered. The frequency and significance of crystalluria in felbamate intoxication is unknown.