Felbamate overdose complicated by massive crystalluria and acute renal failure

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 mug/mL and 370 mug/mL, respectively. Macroscopic urinary crystals formed approximately 18 hours after ingestion and mere identified bg 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.