Methimazole prevents the thyroid gland from producing too much thyroid hormone.
Methimazole is used to treat hyperthyroidism (overactive thyroid). It is also used before thyroid
surgery or radioactive iodine treatment.
Methimazole may also be used for other purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking methimazole?
Do not use this medication if you are allergic to methimazole.
If you have any of these other conditions, you may need a dose adjustment or special tests to
safely take this medication:
liver disease;
a blood cell disorder; or
a weak immune system.
FDA pregnancy category D. This medication can cause harm to an
unborn baby.
Do not use methimazole
without your doctor's consent if you are
pregnant. Tell your doctor if you become pregnant during treatment. Use an effective form of birth
control while you are using this medication.
Methimazole can pass into breast milk and may harm a nursing baby.
Do not use
methimazole if you are breast-feeding a baby.
How should I take methimazole?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger
amounts, or take it for longer than recommended by your doctor. Follow the directions on your
prescription label.
Take methimazole with a full glass of water.
Methimazole can be taken with or without food, but you should take it the same way each time.
Methimazole can increase your risk of bleeding. If you need to have any type of surgery,
tell the surgeon ahead of time that you are using this medication.
Methimazole can lower the blood cells that help your body fight infections. This can make it
easier for you to get sick from being around others who are ill. To be sure your blood cells do not get
too low, your blood will need to be tested on a regular basis. Do not miss any scheduled visits to your
doctor.
It is important to use methimazole regularly to get the most benefit. Get your prescription
refilled before you run out of medicine completely.
Keep using this medication even if you feel fine or have no symptoms of hyperthyroidism.
You may need to keep taking methimazole long term to control your condition. Stopping the
medication could cause your symptoms to return.
Store methimazole at room temperature away from moisture and heat.
What happens if I miss a dose of methimazole?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the
missed dose and take the medicine at your next regularly scheduled time.
Do not
take
extra medicine to make up the missed dose.
Where can I get more information about methimazole?
Your pharmacist has information about methimazole written for health professionals that you may read.
What are the possible side effects of methimazole?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop taking methimazole and call your doctor at once if you have any of these serious side
effects:
fever, chills, sore throat, body aches, flu symptoms;
easy bruising or bleeding, unusual weakness;
blood in your urine or stools;
severe blistering, peeling, and red skin rash; or
nausea, stomach pain, low fever, loss of appetite, dark
urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Less serious side effects may include:
headache, drowsiness, dizziness;
mild nausea, vomiting, or stomach upset;
itching, minor skin rash;
muscle, joint, or nerve pain;
swelling; or
hair loss.
This is not a complete list of side effects and others may occur. Call your
doctor for medical advice about side effects. You may report side effects to FDA at
1-800-FDA-1088. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about methimazole?
Do not take methimazole if you are breast-feeding a baby.
Do not use this medication without telling your doctor if you are pregnant. It could cause
harm to the unborn baby. Use an effective form of birth control, and tell your doctor if you become
pregnant during treatment.
Methimazole can increase your risk of bleeding. If you need to have surgery, tell the
surgeon ahead of time that you are using this medication.
Methimazole can lower the blood cells that help your body fight infections. This can make it
easier for you to get sick from being around others who are ill. To be sure your blood cells do not get
too low, your blood will need to be tested on a regular basis. Do not miss any scheduled visits to your
doctor.
Do not receive a "live" vaccine while you are being treated with methimazole, and avoid
coming into contact with anyone who has recently received a live vaccine. There is a chance that the
virus could be passed on to you.
Keep using this medication even if you feel fine or have no symptoms of hyperthyroidism.
You may need to keep taking methimazole long term to control your condition. Stopping the
medication could cause your symptoms to return.
What should I avoid while taking methimazole?
Avoid being near people who have colds, the flu, or other contagious illnesses. Contact your
doctor at once if you develop signs of infection.
Do not receive a "live" vaccine while you are being treated with methimazole, and avoid
coming into contact with anyone who has recently received a live vaccine. There is a chance that the
virus could be passed on to you.
What other drugs will affect methimazole?
Before taking methimazole, tell your doctor if you are using any of the following drugs:
theophylline (Theo-Dur, Elixophyllin, Uniphyl, and others);
a blood thinner such as warfarin (Coumadin);
digoxin (digitalis, Lanoxin); or
a beta-blocker such as acebutolol (Sectral), atenolol
(Tenormin), betaxolol (Kerlone), bisoprolol (Zebeta), carteolol (Cartrol), carvedilol (Coreg),
esmolol (Brevibloc), labetalol (Normodyne, Trandate), metoprolol (Lopressor, Toprol), nadolol
(Corgard), penbutolol (Levatol), pindolol (Visken), propranolol (Inderal, InnoPran), sotalol
(Betapace), or timolol (Blocadren).
This list is not complete and there may be other drugs that can interact with
methimazole. Tell your doctor about all your prescription and over-the-counter medications, vitamins,
minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication
without telling your doctor.
What happens if I have an overdose of methimazole?
Remember, keep this and all other medicines out of the reach of children, never share
your medicines with others, and use this medication only for the indication prescribed.
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up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum
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given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information
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Content provided by Multum - Last Updated 11/10/2009