Table 2.

Crude incidence of hepatotoxic events associated with individual antithyroid drugs

Events	Events/PYs	Rate/1000 PYs (95% CI)
PTU (n = 24 941)
Hepatitis	21/17 683	1.19 (0.74, 1.82)
Acute liver failure	12/17 683	0.68 (0.35, 1.19)
Cholestasis	4/17 685	0.23 (0.06, 0.58)
Liver transplant	1/17 688	0.06 (0.01, 0.32)
MMI/CBM (n = 46 438)
Hepatitis	118/37 273	3.17 (2.62, 3.79)
Acute liver failure	12/37 308	0.32 (0.17, 0.56)
Cholestasis	9/37 307	0.24 (0.11, 0.46)
Liver transplant	0/37 310	NA

CBM, carbimazole; CI, confidence interval; MMI, methimazole; NA, not applicable; PTU, propylthiouracil; PYs, person-years.