Abstract
Carbimazole, a thionamide derivative, is widely used for hyperthyroidism but carries a rare risk of hepatotoxicity, including cholestatic injury. A 42-year-old man developed severe cholestatic jaundice 4 weeks after carbimazole initiation. Laboratory findings showed marked hyperbilirubinemia (peak: 650 μmol/L) with elevated ALP (366 U/L). Viral, autoimmune, and biliary causes were excluded. Liver biopsy confirmed cholestasis. Carbimazole was discontinued, corticosteroids initiated, and radioiodine therapy planned. Bilirubin levels gradually improved over 8 weeks. Carbimazole-induced cholestasis, though rare, necessitates prompt recognition and alternative hyperthyroidism management. Routine liver monitoring is crucial.