Methimazole is used to treat hyperthyroidism, a condition that occurs when the thyroid gland produces too much thyroid hormone. It also is taken before thyroid surgery or radioactive iodine therapy.

How should this medicine be used?
Methimazole comes as a tablet and usually is taken three times a day, approximately every 8 hours, with food. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.
What special precautions should I follow?

Before taking methimazole
tell your doctor and pharmacist if you are allergic to methimazol, lactose, or any other drugs.
tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially anticoagulants ('blood thinners') such as warfarin (Coumadin), beta blockers such as propranolol (Inderal), diabetes medications, digoxin (Lanoxin), theophylline (Theobid, Theo-Dur), and vitamins.
tell your doctor if you have or have ever had any blood disease, such as decreased white blood cells (leukopenia), decreased platelets (thrombocytopenia), or aplastic anemia, or liver disease (hepatitis, jaundice).
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. Methimazole should not be used during pregnancy or breast-feeding. If you become pregnant while taking methimazole, call your doctor immediately. Methimazole may harm the fetus.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking methimazole.

What special dietary instructions should I follow?

Methimazole may cause an upset stomach. Take methimazole with food or milk.