You should not breast-feed while using  methimazole.
Before taking this medicine
You should not use methimazole if you are allergic to it, or:
if you are pregnant or breast-feeding.
To make sure methimazole is safe for you, tell your doctor if you have:
liver disease;
a blood cell disorder; or
a weak immune system.
Using methimazole during pregnancy could harm the unborn baby. Tell your doctor if you are pregnant or if you become pregnant while using this medicine.
Methimazole can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.
Do not give this medicine to a child without medical advice.
How should I take methimazole?
Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use  methimazole in larger or smaller amounts or for longer than recommended.
Methimazole is usually taken every 8 hours. Take your doses at regular intervals to keep a steady amount of the drug in your body at all times.
If a child is using this medicine, tell your doctor if the child has any changes in weight. Methimazole doses are based on weight in children, and any changes may affect your child's dose.
Methimazole can lower blood cells that help your body fight infections and help your blood to clot. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. Your blood may need to be tested often.
Use methimazole regularly to get the most benefit, even if you feel fine or have no symptoms of hyperthyroidism. Get your prescription refilled before you run out of medicine completely.
If you need surgery, tell the surgeon ahead of time that you are using methimazole.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include nausea, vomiting, upset stomach, headache, joint pain, fever, itching, swelling, or pale skin and easy bruising or bleeding.
