Hyperthyroidism radioactive iodine treatment: what to know

The thyroid uses iodine to make hormones, so the treatment concentrates there and gradually lowers hormone production.

A nuclear medicine team gives radioactive iodine as a capsule or liquid. The dose is chosen for your thyroid problem. Effects develop gradually rather than immediately, and blood tests help track thyroid hormone levels. Many people later need thyroid hormone replacement because the gland becomes underactive.

Tell the clinician if you are pregnant, trying to conceive, breastfeeding, or taking thyroid medicines. Pregnancy and breastfeeding require special planning. You may receive temporary advice about close contact, hygiene, and handling bodily fluids after treatment.

Follow the treatment team’s instructions about stopping or restarting medicines, food or drink, and contact precautions. Keep every blood-test appointment, even if symptoms improve. Report worsening tremor, heat intolerance, sweating, diarrhoea, anxiety, or palpitations so treatment can be reviewed.

Seek urgent medical help for severe breathlessness, chest pain, fainting, confusion, or a very fast or irregular heartbeat. Contact your treating team promptly if you develop marked neck swelling, trouble swallowing, or symptoms that rapidly intensify.

Ask why radioactive iodine suits your situation, which medicines need changing, how long precautions last, when hormone tests are due, and what symptoms suggest your thyroid has become underactive.