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Name of the Generic: methimazole me-THIM-a-zole me-THIM-a-zole
Brand Names: Tapazole, Northyx
Dosage Format: Oral tablet (10 mg, 5 mg)
Class of Drugs: Antithyroid agents

What is Methimazole?

Methimazole helps stop your thyroid gland from producing excessive thyroid hormone.Methimazole is a treatment for the condition of hyperthyroidism (overactive thyroid). It is also prescribed prior to the thyroid operation and radioactive iodine treatment.

Methimazole can also be employed for other purposes that are not covered in this medication guideline.

Side effects of Methimazole

Contact a medical professional immediately. Get medical attention immediately if you notice symptoms that indicate an allergic reaction, such as hives, difficulty breathing, or swelling of your lips, face, or tongue.

Infections that are fatal and often deadly can occur when you are using methimazole. Stop taking methimazole and consult your physician right away when you show symptoms of infection, such as:

  • A sudden feeling of weakness or discomfort, fever, chills, sore throat, cold or flu symptoms;
  • Painful mouth sores, discomfort when swallowing, swelling or red gums,
  • Pale skin, no bruising, or unusual bleeding.

Methimazole could cause severe adverse effects. Consult your physician right away. If you suffer from:

  • Swollen glands in your neck or jaw
  • Liver issues: symptoms include nausea and stomach pains in the upper part of the stomach, itching, fatigue, and a loss of appetite. the dark color of urine, the clay-coloured stool, and jaundice (yellowing of the eyes or skin).

Common side effects of methimazole include:

  • Nausea, vomiting, upset stomach;
  • Headache, dizziness, or drowsiness;
  • Sensation of tingling or numbness;
  • Rash, itching, and skin discoloration;
  • Muscles or joint discomfort;
  • Hair loss,
  • Reduced sensation of tasting.

This is not a comprehensive list of all the side effects. Other effects may also be present. Contact your doctor to seek medical advice on the effects. You can report any adverse reactions to the FDA at 1-800-FDA-1088.


It is not recommended to breastfeed when taking this medication.

Before you Take this Drug

It is not recommended to use methimazole if you have a reaction to it or if:

  • If you are pregnant or breastfeeding.

To ensure that methimazole is suitable for you, inform your doctor if:

  • The liver condition;
  • A blood cell disorder;
  • A weak immune system.

The use of methimazole during pregnancy can cause harm to the baby. Consult your physician if you are expecting or get pregnant while taking methimazole.

Methimazole may be absorbed into breast milk and could cause harm to a nursing infant. Do not breastfeed while taking this medicine.Don't give the medication to an infant without medical guidance.

How to Take Methimazole?

Follow the directions on the prescription label. Your doctor might modify your dose. Don't take this medication in greater or lesser quantities or for longer periods than prescribed.

Methimazole is typically taken every 8-hour period. Make sure to take your doses on a regular basis to maintain a consistent quantity of the drug in your body throughout the day.

If your child is taking this medication, tell your doctor if they show any change in their weight. Methimazole dosages are based on the weight of children, and any changes could affect the dosage of your child.

Methimazole is a drug that can reduce blood cells, which help your body fight off infections and ensure that your blood can stop clotting. This makes it more likely for you to get a blood clot from an injury or become sick when you are around people who are sick. Your blood might require frequent testing.

Make sure you take methimazole on a regular basis to reap maximum benefit, even if you are feeling well or don't have any symptoms of hyperthyroidism. Refill your prescription before running out of the medicine completely.If you require surgery, inform the surgeon in advance that you're using methimazole.Keep at room temperature, away from heat and moisture.

Details on Dosage

Usual Adult Dose for Hyperthyroidism:

Initial dose:
Hyperthyroidism mild: 15 mg per day
Moderately severe hyperthyroidism: 30–40 mg taken orally daily
Hyperthyroidism severe: 60 mg taken daily orally
Maintenance dose:
Between 5 and 15 mg daily
Comments Doses for the day are typically delivered in three doses that are given at 8-hour intervals.
for treating Graves disease and toxic nodular goiter, for which radioactive iodine therapy or surgery is not the best treatment alternative.
To reduce symptoms of hyperthyroidism prior to preparation to undergo thyroidectomy or radiation treatment with iodine.

Usual Paediatric Dose for Hyperthyroidism:

The first dose is 0.4 mg/kg, orally daily.
Dosage for maintenance: 0.2 mg/kg orally per day (approximately one-fifth of the dose at first).
The daily doses are generally delivered in three divided doses that are given at 8-hour intervals.

What Happens if I Miss the Dose?

You should take the dose you missed as soon as you can remember. Avoid any missed doses if you are close to the time of your next dose. Don't take any extra medication to make up for the missed dose.

What Happens If I Overdose?

Get medical attention in an emergency or contact the Poison Help line toll-free at 1-800-222-1222.

The symptoms of an overdose can include vomiting, nausea, headache, stomach upset, joint discomfort, fever, itching, an increase in the size of the skin, and bleeding or bruising that is easy to stop.

What Should be Avoided?

Beware of those who are sick or suffering from infections. Contact your doctor right away when you begin to show symptoms of an infection.

Interaction with Other Drugs

Inform your doctor about all your medications currently in use and any new medications you begin or stop taking, in particular:

  • Digoxin, digitalis, theophylline;
  • A blood thinner (warfarin, Coumadin, Jantoven)
  • Beta blockers: carvedilol, atenolol, labetalol, metoprolol, propranolol, nadolol, and others

This list isn't complete. Other drugs can be incompatible with methimazole, such as medications that are prescribed and available over the counter, vitamins, and herbal products. There are many possible interactions that are not included in this guide to medication.




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