The serum concentration of Aminophylline can be increased when it is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Phenindione. The serum concentration of Theophylline can be increased when it is combined with Methimazole. The serum concentration of Bosutinib can be increased when it is combined with Methimazole. The serum concentration of Simvastatin can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Dihydroergotamine is combined with Methimazole. The risk or severity of adverse effects can be increased when Bromocriptine is combined with Methimazole. The therapeutic efficacy of Iodide I-131 can be decreased when used in combination with Methimazole. The risk or severity of adverse effects can be increased when Lysergic Acid Diethylamide is combined with Methimazole. The serum concentration of Lovastatin can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Ergotamine is combined with Methimazole. The serum concentration of Fluvastatin can be increased when it is combined with Methimazole. The serum concentration of Cilostazol can be increased when it is combined with Methimazole. The serum concentration of Digoxin Immune Fab (Ovine) can be increased when it is combined with Methimazole. The serum concentration of Ubidecarenone can be increased when it is combined with Methimazole. The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Methimazole. Methimazole may decrease the anticoagulant activities of Warfarin. The serum concentration of Mevastatin can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Methimazole is combined with Atorvastatin. The serum concentration of Acetyldigitoxin can be increased when it is combined with Methimazole. The serum concentration of Digoxin can be increased when it is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Dicoumarol. The risk or severity of adverse effects can be increased when Methimazole is combined with Clozapine. The serum concentration of Oleandrin can be increased when it is combined with Methimazole. The serum concentration of Tizanidine can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Cabergoline is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Ethyl biscoumacetate. The serum concentration of Ibrutinib can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Methylergometrine is combined with Methimazole. The risk or severity of adverse effects can be increased when Ergonovine is combined with Methimazole. The risk or severity of adverse effects can be increased when Pergolide is combined with Methimazole. The serum concentration of Ouabain can be increased when it is combined with Methimazole. The serum concentration of Rosuvastatin can be increased when it is combined with Methimazole. The serum concentration of Cerivastatin can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Lisuride is combined with Methimazole. The risk or severity of adverse effects can be increased when Nicergoline is combined with Methimazole. The serum concentration of Tolvaptan can be increased when it is combined with Methimazole. The serum concentration of Thioridazine can be increased when it is combined with Methimazole. The serum concentration of Prednisolone can be decreased when it is combined with Methimazole. The risk or severity of myelosuppression can be increased when Metamizole is combined with Methimazole. The risk or severity of adverse effects can be increased when Metergoline is combined with Methimazole. The serum concentration of the active metabolites of Artesunate can be reduced when Artesunate is used in combination with Methimazole resulting in a loss in efficacy. The serum concentration of Pravastatin can be increased when it is combined with Methimazole. The serum concentration of Dyphylline can be increased when it is combined with Methimazole. The serum concentration of Rilpivirine can be increased when it is combined with Methimazole. The risk or severity of adverse effects can be increased when Methysergide is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Fluindione. The serum concentration of Ambroxol acefyllinate can be increased when it is combined with Methimazole. The serum concentration of Proscillaridin can be increased when it is combined with Methimazole. The serum concentration of Pitavastatin can be increased when it is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Acenocoumarol. The serum concentration of Deslanoside can be increased when it is combined with Methimazole. Methimazole may decrease the anticoagulant activities of Phenprocoumon. The serum concentration of Digitoxin can be increased when it is combined with Methimazole. The serum concentration of Metoprolol can be increased when it is combined with Methimazole.