Case Report of A Rare Idiosyncratic Hepatotoxicity Induced by Valproic Acid

Valproate induced hepatotoxicity is a well-known side effect, which frequently required periodic monitoring of serum drug level. Hepatotoxicity caused by valproate typically occurs at supratherapeutic drug levels. Once in a while, an idiosyncratic reaction is elicited, liver injury might occur despite normal serum valproate level mainly in chronic users. We hereby identify an unusual case of acute idiosyncratic valproate induced hepatotoxicity. We report a case of a 65 years old male with dyslipidemia and history of seizure, on valproic acid therapy, presented with altered mental status and drowsiness. The patient’s home medications include only zenil 10 mg daily and valproate which was started one month ago. At presentation, He was awake, oriented, but lethargic. Laboratory testing reveals hepatocellular injury with elevated transaminase levels, direct hyperbilirubinemia and coagulopathy. The ammonia level was normal and valproate level was within the therapeutic range. Abdomen computed tomography with IV contrast and MRCP results were irrelevant. Idiosyncratic valproate toxicity was diagnosed after exclusion of all other possible etiologies and after a rapid clinical and laboratory improvement once the drug was discontinued. Based on the patient’s clinical context the diagnosis of valproate induced hepatotoxicity was confirmed. This case emphasizes the importance of identifying, diagnosing, and managing valproate toxicity when no alternative clarification for their symptoms. We need further attempts and more researches to improve the detection of adverse hepatic reactions and to obtain reliable information about the discovery of new biomarkers or tools for early prediction of DILI, as well as to obtain accurate information on epidemiology, drug safety, and pathogenesis in order to improve management for better survival.