Common use

Methimazole is an antithyroid medication used to treat hyperthyroidism, a condition where the thyroid gland produces excessive hormones. It is often prescribed for Graves' disease, the most common cause of overactive thyroid. Methimazole works by inhibiting thyroid hormone synthesis, helping to restore normal thyroid levels. In some cases, it is used before surgery or radioactive iodine treatment.

Dosage and direction

The dosage of methimazole varies based on the severity of hyperthyroidism:

• Typical starting dose: 5-30 mg daily, divided into multiple doses.
• Dosage is reduced for maintenance once thyroid levels normalize.
• Take tablets at the same time each day, with or without food.

Follow your doctor's instructions carefully and do not adjust the dose without medical advice.

Precautions

• Inform your doctor if you have liver disease, blood disorders, or a history of allergies.
• Regular blood tests are required to monitor thyroid function and blood cell counts.
• Watch for signs of infection, fever, or sore throat due to potential effects on white blood cells.
• Not recommended during the first trimester of pregnancy unless alternatives are unavailable.

Contraindications

• Hypersensitivity to methimazole.
• Avoid in the first trimester of pregnancy (risk of birth defects) unless prescribed.
• Not for patients with serious blood disorders or preexisting liver problems.

Consult a healthcare provider before starting or stopping treatment.

Possible side effects

• Common: Skin rash, nausea, headache, joint pain.
• Serious (rare): Agranulocytosis, hepatitis, vasculitis.

Seek immediate medical attention for fever, sore throat, or unusual bruising. Most side effects are reversible if detected early.

Drug interactions

• May interact with blood thinners (e.g., warfarin), beta-blockers, and theophylline.
• Can alter effects of digoxin and other thyroid medications.

Disclose all medications and supplements to your doctor. Avoid iodine-containing supplements unless prescribed.

Missed dose

If you miss a dose:

• Take it as soon as you remember.
• If near the next dose, skip the missed dose, do not double it.

Consistency is key for stable thyroid levels. Use reminders to avoid missed doses.

Overdose

Symptoms of overdose (hypothyroidism) may include:

• Fatigue.
• Weight gain.
• Cold intolerance.

Seek medical help immediately. Treatment is symptom-based. Never exceed the prescribed dose.

Storage

• Store at room temperature (20°C-25°C / 68°F-77°F).
• Protect from light, moisture, and heat.
• Keep in the original tightly closed container.
• Store out of reach of children and pets.
• Dispose of expired medication per local guidelines.

Disclaimer

This information provides general guidance only and does not cover all possible directions, interactions, or precautions. It should not be used for self-diagnosis or self-treatment. Always consult your healthcare provider for personalized advice. We do not guarantee the accuracy of this content and disclaim liability for any errors or consequences of its use.