What is the first treatment tried for hyperthyroidism?

An overactive thyroid can cause symptoms such as a racing heartbeat, tremor, heat intolerance, sweating, anxiety, weight loss or frequent bowel movements. These symptoms can have other causes, so a clinician usually confirms the pattern with a Thyroid Function Test and asks about medicines, heart problems, pregnancy and previous thyroid disease.

Antithyroid medicine can reduce new thyroid hormone production, but the appropriate option and monitoring plan vary. A beta blocker may sometimes be used for symptoms such as a fast heartbeat while the thyroid treatment takes effect; this is not suitable for everyone.

Arrange a [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) if symptoms suggest an overactive thyroid. Take medicine exactly as prescribed and attend requested blood tests, because the dose may need adjustment as hormone levels change. Do not start iodine supplements or stop prescribed treatment without advice.

Explore [Thyroid Function Test](/treatments/diagnostics-and-screening/thyroid-function-test/) and read about [Hyperthyroidism](/conditions/hyperthyroidism/) to understand the condition and follow-up.

Seek emergency help for chest pain, severe breathlessness, fainting, marked confusion, or a very fast or irregular heartbeat with feeling unwell. While taking antithyroid medicine, seek prompt medical advice for fever, a severe sore throat, mouth ulcers or yellowing of the skin, as these can need urgent review.

What is causing my overactive thyroid? Which blood tests will monitor treatment? What symptoms should improve first? Which side effects need prompt advice? Are there medicines or supplements I should avoid?