Methimazole (Oral)

Methimazole (By Mouth)

Methimazole (meth-IM-a-zole)

Treats hyperthyroidism (too much thyroid hormone produced by the thyroid gland).

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to methimazole or carbimazole, or if you are pregnant or breastfeeding.

How to Use This Medicine:


  • Your doctor will tell you how much of this medicine to take and how often. Do not take more medicine or take it more often than your doctor tells you to.  
  • You may take this medicine with or without food.  
  • It is best to take this medicine at the same time every day.

If a dose is missed::

  • If you miss a dose or forget to take your medicine, take it as soon as you can. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose.  
  • Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine at room temperature, away from heat, moisture, and direct light.  
  • Keep all medicine out of the reach of children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are using a blood thinner (Coumadinreg;), blood pressure medicine (such as atenolol, metoprolol, propranolol, Corgardreg;, Inderalreg;, Lopressorreg;, Toprolreg;, Tenorminreg;), digoxin (Lanoxinreg;), or theophylline (Theo-Durreg;).

Warnings While Using This Medicine:

  • Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.  
  • Make sure any doctor or dentist who treats you knows that you are using this medicine.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Dark-colored urine, pale stools  
  • Fever, chills, cough, sore throat  
  • Nausea, vomiting, loss of appetite, pain in the upper stomach  
  • Numbness, tingling, or burning in your hands or feet  
  • Severe skin rash or itching  
  • Unusual bruising or bleeding  
  • Unusual weakness or tiredness  
  • Yellow skin or eyes

If you notice these less serious side effects, talk with your doctor:

  • Dizziness  
  • Joint pain  
  • Mild nausea and vomiting, stomach upset  
  • Mild skin rash

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: June 18, 2011
Last revised: by Janet A. Staessen, MD, PhD

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

The drug reference included in this section is provided by Cerner Multum, Inc., of Denver, Colorado. Armenian Medical Network receives monthly updates from Multum.