Methimazole

Description

Methimazole is used for the treatment of hyperthyroidism, a condition where the thyroid gland produces an excessive amount of thyroid hormones. It is also used to relieve the symptoms of hyperthyroidism before thyroid surgery or radioactive iodine treatment. This medicine works by inhibiting the secretion of thyroid hormones, thus reducing its level. Methimazole can cause side effects like nausea, vomiting, back pain, cough, etc. Most of these are temporary and resolve within some time. Consult your doctor if these side effects persist or worsen. Methimazole is taken with food to avoid stomach discomfort. Take this medicine at the same time every day to maintain a constant level of medicine in your blood. Do not stop taking this medicine without consulting your doctor as your symptoms could reoccur. Methimazole is not recommended if you are allergic to it. Inform your doctor about your current medications and medical conditions before taking this medicine. This will help your doctor to adjust your dose for avoiding any side effects. If you are pregnant or breastfeeding, consult your doctor before taking this medicine.

Side effects

Major & minor side effects for Methimazole

  • Back pain
  • Chest pain
  • Fever
  • Cough
  • Sore throat
  • Yellow eyes or skin
  • Nausea and vomiting
  • Rash

Uses of Methimazole

What is it prescribed for?

  • Hyperthyroidism
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Concerns

Commonly asked questions

  • Onset of action
    The amount of time required for Methimazole to show its action is 12 to 18 hours of intake.
  • Duration of effect
    The duration for which Methimazole remains active in your body is 36 to 72 hours of intake.
  • Safe with alcohol?
    Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.
  • Is it habit forming?
    No habit-forming tendencies were reported for Methimazole.
  • Usage in pregnancy?
    Methimazole is not recommended for use in pregnancy as this medicine may affect your developing foetus. Discuss all the risks and benefits with your doctor before taking this medicine.
  • Usage while breast-feeding?
    Methimazole is not recommended if you are breastfeeding as it passes into breast milk. Consult your doctor before taking this medicine.

Allergy

Methimazole is not recommended if you are allergic to it. Seek immediate medical attention if you notice any symptoms such as skin rash, itching/swelling (especially of your face/tongue/throat), severe dizziness, breathing difficulty, etc.
Warnings for special population

Pregnancy

Methimazole is not recommended for use in pregnancy as this medicine may affect your developing foetus. Discuss all the risks and benefits with your doctor before taking this medicine.

Breast-feeding

Methimazole is not recommended if you are breastfeeding as it passes into breast milk. Consult your doctor before taking this medicine.
General warnings

Hypothyroidism

Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland does not produce essential hormones to the body. Methimazole should be used with caution as it may excessively lower your thyroid levels and cause hypothyroidism.

Agranulocytosis

Agranulocytosis is a condition involving a severe and dangerous lowered white blood cell count. Methimazole should be used with extreme caution if you have this disorder as it may worsen your condition. Consult your doctor if you develop pale skin, fever, chills, weakness, fatigue etc.

Surgeries

Methimazole should be used with extreme caution while planning for surgeries as it may cause excessive bleeding. Your doctor may stop this medicine prior to your surgery or adjust the dose for your safety.

Missed Dose

The missed dose of Methimazole should be taken as soon as possible. It is advisable to skip the missed dose if it is already time for your next scheduled dose. Do not use extra medicine to make up for the missed dose.

Overdose

Seek emergency medical treatment in case of an overdose of Methimazole.
All drugs interact differently for person to person. You should check all the possible interactions with your doctor before starting any medicine.
Interaction with Alcohol

Description

Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.

Instructions

Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.
Interaction with Medicine

Prednisolone

Leflunomide

Anticoagulants

Fluphenazine

Teriflunomide

Efavirenz

Clozapine

Carvedilol

Disease interactions

Liver Disease

Methimazole is broken down and converted into its active form for absorption in your body. If you have liver problems, accumulation of this medicine may take place in the liver leading to worsening of compromised liver and other undesirable effects.

Blood Dyscrasias

Methimazole should be used with caution if you have blood dyscrasias (any disorder of the blood) as it may lower your blood cells which may worsen your condition. Your doctor may regularly monitor your blood cell count and/or adjust your dose if required.

Bleeding disorders

Methimazole should be used with caution if you have any bleeding disorders as it may lower your blood cells and increase bleeding. Your doctor may adjust your dose or replace it with another medicine if required.
Food interactions
Information not available.
Lab interactions
Information not available.
You should take Methimazole as instructed by your doctor. Do not crush, break or chew the tablets. Methimazole is given for the long term. Therefore, complete the whole treatment for maximum benefits. Keep Methimazole away from children and pets. Throw away the unused medicine safely after the expiry date. You should not take this medicine in larger amounts than prescribed. Consult the doctor if you experience any undesirable side effects.
Miscelleneous

To be taken with food

To be taken as instructed by doctor

May cause sleepiness

How it works
Methimazole is composed of Methimazole. It inhibits the synthesis of thyroid hormone to reduce thyroid hormone levels and thus relieves associated symptoms.
Legal Status

Approved

Approved

Approved

Unknown

Classification

Category

Antithyroid agents

Schedule

Schedule H

Pubchem.ncbi.nlm.nih.gov. 2021. Methimazole. [online] Available at: < [Accessed 6 December 2021].

https://pubchem.ncbi.nlm.nih.gov/compound/methimazole>

Accessdata.fda.gov. 2021. [online] Available at: < [Accessed 6 December 2021].

https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/040350s016lbl.pdf>

Dailymed.nlm.nih.gov. 2021. Tapazole® Methimazole Tablets, USP. [online] Available at: < [Accessed 6 December 2021].

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4280e008-bbaf-4cc7-b588-3b4303016067>

Drugs, H., 2021. Methimazole: MedlinePlus Drug Information. [online] Medlineplus.gov. Available at: < [Accessed 6 December 2021].

https://medlineplus.gov/druginfo/meds/a682464.html>

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Information on this page was last updated on 28 Dec 2021

Disclaimer

We’ve made all possible efforts to ensure that the information provided here is accurate, up-to-date and complete, however, it should not be treated as a substitute for professional medical advice, diagnosis or treatment. Practo only provides reference source for common information on medicines and does not guarantee its accuracy or exhaustiveness. The absence of a warning for any drug or combination thereof, should not be assumed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Practo does not assume any responsibility for any aspect of healthcare administered with the aid of information provided above. If you have any doubts about your medication then we strongly recommend that you consult with your doctor, nurse or healthcare provider. See detailed T&C here.