Thyroid Medicines: A Complete Guide for Patients
Thyroid disorders are among the most common hormonal conditions in India, affecting approximately 42 million people. Whether you have hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid), understanding your thyroid medicine is crucial for effective management.
Medicines for Hypothyroidism (Underactive Thyroid)
Levothyroxine (L-thyroxine)
Brand names: Eltroxin, Thyrox, Thyronorm
Levothyroxine is a synthetic form of the thyroxine (T4) hormone produced by the thyroid gland. It is the gold-standard treatment for hypothyroidism worldwide.
How to Take Levothyroxine Correctly
- Take on an empty stomach, 30–60 minutes before breakfast or at bedtime (at least 3 hours after the last meal)
- Swallow with a full glass of water only — not coffee, milk, or juice
- Take at the same time every day
- Never skip or double dose
What Interferes with Levothyroxine Absorption
- Calcium supplements — take 4 hours apart
- Iron supplements — take 4 hours apart
- Antacids containing calcium or magnesium — take 4 hours apart
- Soy products and high-fibre foods — can reduce absorption
- Coffee — even 1 hour after taking levothyroxine reduces absorption significantly
Monitoring Levothyroxine Treatment
- TSH should be checked 6–8 weeks after starting or changing dose
- Once stable, check TSH every 6–12 months
- Target TSH: 0.5–2.5 mIU/L for most adults (may vary by age and pregnancy status)
- Dose may need adjustment after weight changes, pregnancy, or new medications
Side Effects of Over-Treatment (Too Much Levothyroxine)
Taking too much causes symptoms of hyperthyroidism: palpitations, anxiety, insomnia, weight loss, tremor, sweating, and long-term osteoporosis.
Medicines for Hyperthyroidism (Overactive Thyroid)
Carbimazole
Brand names: Neomercazole, Carbimazole tablets
Carbimazole blocks the thyroid from producing hormones. It is the most commonly used antithyroid drug in India.
- Usually given 2–3 times daily
- Effects take 4–8 weeks to fully manifest
- Regular blood tests needed to monitor thyroid function
Important warning: Carbimazole can rarely cause agranulocytosis (dangerous drop in white blood cells). Seek immediate medical attention for sore throat, fever, or mouth ulcers while on carbimazole — this requires urgent blood testing.
Propylthiouracil (PTU)
An alternative to carbimazole; preferred in the first trimester of pregnancy as carbimazole has teratogenic concerns. Requires more frequent dosing (3 times daily).
Beta Blockers for Symptom Control
Propranolol or atenolol are often added initially to control palpitations, tremor, and anxiety while waiting for antithyroid medicines to take effect. They don’t treat the underlying thyroid overactivity.
Radioactive Iodine (RAI) and Surgery
For long-term management of hyperthyroidism, radioactive iodine or thyroid surgery are options. After RAI or surgery, patients typically develop hypothyroidism and require lifelong levothyroxine.
Special Considerations
Pregnancy and Thyroid Medicine
Thyroid disorders require especially careful monitoring during pregnancy. Uncontrolled hypothyroidism affects foetal brain development. Levothyroxine dose often needs to increase by 25–30% in pregnancy. Consult your endocrinologist immediately upon discovering pregnancy.
Never Stop Thyroid Medicine Without Medical Advice
Hypothyroidism requires lifelong treatment in most cases. Stopping levothyroxine causes return of all symptoms and risks serious complications including myxoedema coma in severe hypothyroidism.
Monitor Your Thyroid at Dashvanth Healthcare
Our diagnostic laboratory offers TSH, Free T3, and Free T4 testing with rapid turnaround. Our pharmacy stocks all major thyroid medicines. We can also advise on optimal timing of levothyroxine doses relative to your other medications.
