Unlike some drug-induced hepatitis, about half of the cases of methimazole-induced hepatitis continue for eight to ten weeks after use of the drug is discontinued. If stopping therapy with the drug fails to produce resolution of the process, percutaneous transhepatic cholangiography should be performed. If the biliary system cannot thus be visualized, a period of at least ten weeks must be allowed to elapse, despite the deepening jaundice, before the diagnosis of methimazoleinduced hepatitis can be abandoned and laparotomy considered.
Fischer MG, Nayer HR, Miller A. Methimazole-Induced Jaundice. JAMA. 1973;223(9):1028-1029. doi:10.1001/jama.1973.03220090048010