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Is Your Overactive Thyroid Causing Racing Heartbeats and Weight Loss? What You Need to Know About Methimazole Tablets

Dr. Priya Sammani (MBBS)
Medically Reviewed by Dr. Priya Sammani (MBBS) ✓ Medically Reviewed
📅 Updated: Oct 20, 2026 • ⏱ 3 min read • Editorial Policy
Is Your Overactive Thyroid Causing Racing Heartbeats and Weight Loss? What You Need to Know About Methimazole Tablets

Have you been feeling unusually jittery, losing weight without trying, or noticing that your heart feels like it is racing even when you are resting? These are classic signs that your thyroid gland might be working overtime, a common medical condition known as hyperthyroidism. When your body produces too many thyroid hormones, your entire system goes into overdrive, leaving you exhausted, anxious, and physically depleted.

If your doctor has diagnosed you with an overactive thyroid, they may have prescribed a medicine called Methimazole. Perhaps you are already taking these small pills every day, or maybe a loved one has recently received a prescription for them. Understanding how this medicine works, how to take it safely, and what side effects to watch out for is one of the best ways you can take control of your health journey.

Navigating a new medical diagnosis can feel overwhelming, but you do not have to figure it out alone. In this complete guide, we will break down everything you need to know about Methimazole tablets in clear, everyday language so you can feel confident every single day.

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❓ FAQ

Frequently Asked Medical Questions (FAQ)

Evidence-based clinical answers to common patient questions

How long do I need to take Methimazole tablets?

Treatment duration varies for everyone depending on how your thyroid responds. Most patients take Methimazole for 12 to 18 months, after which your doctor will evaluate whether your hormone levels remain stable without medicine.

Will Methimazole cause me to gain weight?

Hyperthyroidism speeds up your metabolism, often causing weight loss. As Methimazole calms your thyroid down, your metabolism returns to normal, which may lead to healthy weight restoration. Eating a balanced diet and staying active helps manage this.

Can I drink alcohol while taking this medicine?

It is best to limit or avoid alcohol while taking Methimazole. Both alcohol and the medicine can affect your liver, so combining them may increase your risk of liver stress or strain.

What should I do if I feel too tired after starting Methimazole?

As your overactive thyroid slows down, you might initially feel tired as your body adjusts to a calmer state. However, if extreme fatigue persists or feels overwhelming, contact your doctor to check if your dose needs adjustment.

Is it safe to get pregnant while on Methimazole?

Methimazole carries certain risks during early pregnancy. If you are planning to become pregnant, talk to your doctor right away so they can switch you to a safer alternative medicine designed for pregnancy.

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Verified Scientific & Medical References (PubMed / WHO)

✓ Peer-Reviewed Sources
  1. Calms Overactive Glands: Methimazole slows down your thyroid gland so it stops making too many hormones.
  2. Consistency is Crucial: Take your dose at the exact same time every single day with water.
  3. Never Stop Suddenly: Stopping your medicine without your doctor can cause your thyroid symptoms to roar back.
  4. Watch for Red Flags: Report sudden fevers, sore throats, or yellowing skin to your doctor right away.
  5. Regular Lab Work: Routine blood tests let your doctor fine-tune your dose for maximum safety.
  6. Tell your doctor if you have any existing liver disease or problems with liver function.
  7. Let them know if your routine blood tests have ever shown a low white blood cell count.
  8. Mention any past allergic reactions to Methimazole, similar anti-thyroid medicines, food colorings, or dyes.
  9. Inform your doctor right away if you are pregnant, trying to conceive, or planning a family soon.
  10. Disclose if you are currently breastfeeding or planning to nurse an infant.
  11. Asthma medicines such as Theophylline or Aminophylline.
  12. Heart and blood pressure drugs like metoprolol, propranolol, or atenolol.
  13. Digoxin, a medicine used for specific heart rhythm conditions.
  14. Warfarin or other blood-thinning medicines that prevent dangerous clots.
  15. Mayo Clinic. Hyperthyroidism Diagnosis and Treatment Overview.
  16. National Health Service (NHS UK). Methimazole and Carbimazole Uses and Side Effects.
  17. Cleveland Clinic. Methimazole Oral Tablets Patient Education.
  18. Centers for Disease Control and Prevention (CDC). Thyroid Health and General Patient Safety Guidelines.
  19. National Institutes of Health (NIH / PubMed). Clinical Pharmacology of Anti-Thyroid Drugs in Hyperthyroidism Management.
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⚠️ Important: Medical articles and information on Nirogi Lanka are strictly for educational and awareness purposes and do not substitute professional medical advice, diagnosis, or treatment. Always consult a qualified physician for any medical concerns.