Acute Mental Status Changes and Hyperchloremic Metabolic Acidosis with Long‐Term Topiramate Therapy

Mental status changes and metabolic acidosis may occur with topiramate therapy. These adverse events were reported during dosage titration and with high dosages of the drug. A 20‐year‐old man receiving topiramate, valproic acid, and phenytoin experienced acute‐onset mental status changes with hyperchloremic metabolic acidosis. He had been receiving a modest dose of topiramate for 9 months. He was weaned off topiramate over 5 days, and his mental status returned to baseline within 48 hours of discontinuing the agent. This case illustrates the need for close evaluation of patients who experience acute‐onset mental status changes during topiramate therapy.