A Case of Acute Liver Failure Associated with Methimazole in Patient with Underlying Liver Disease

ABSTRACT

We report a case of methimazole-induced acute hepatic failure, which occurred 4 days after initiation of drug in a 51-year-old man with hyperthyroidism. Liver function was evaluated before taking methimazole, total bilirubin was 14.2 mg/dL. This finding suggested toxic hepatitis d/t herbal medication or unknown liver disease. He was treated with methimazole with increasing doses from 15 to 45 mg/day, he developed liver failure gradually, despite of suspending methimazole. From the time of admission, his liver function test was abnormal and liver cirrhosis was suspected by liver sonography. With aggravated liver function, he died of renal failure, sepsis of unknown origin and respiratory failure. Fulminant hepatitis rarely occurs in methimazole users, and spontaneous recovery is expected. But this case shows that methimazole-induced hepatotoxicity with possible underlying liver disease could increase the risk of poor outcomes. And in case of continued deterioration of liver function, prompt liver transplatation should be considered.