Carbimazole as compared to propylthiouracil:
(Ref: KDT 6/e p250) Carbimazole Propylthiouracil Produces an active metabolite, methimazole No active metabolite Less plasma protein binding (PPB) More PPB Crosses placenta Does not cross placenta More potent Less potent Does not inhibit 5'-deiodinase Inhibits 5'-deiodinase