Major
Established
描述
The combination of topiramate and valproic acid is associated with hyperammonemia and encephalopathy even without hepatotoxicity, representing a unique metabolic interaction.
机制
Both drugs inhibit carbonic anhydrase and disrupt the urea cycle; topiramate inhibits carbamoyl phosphate synthetase I, and valproate impairs mitochondrial metabolism, resulting in ammonia accumulation.
临床意义
Hyperammonemic encephalopathy can occur without elevated liver enzymes or serum valproate toxicity; the condition is reversible upon drug discontinuation.
处理措施
Monitor ammonia levels if altered mental status develops; reduce or discontinue topiramate if hyperammonemia is confirmed.