Indications
Iodine is a trace mineral found in multivitamin, prenatal and thyroid-support supplements, usually as Potassium Iodide. It is used to prevent iodine deficiency, which can cause goitre (a swollen thyroid gland) and slow thyroid function, and to meet the higher needs of pregnancy and breastfeeding, when iodine is important for the baby’s brain development.
How It Works
The thyroid gland uses iodine to make thyroid hormones, which control the body’s energy use, growth and development, including the development of the baby’s brain and nerves during pregnancy.
Dosage and Administration
Adults usually need about 150 micrograms (mcg) a day from food and supplements together; in pregnancy and breastfeeding about 250 mcg a day is advised. Follow the dose on the supplement label, and remember that iodised salt also provides iodine. Do not take high-dose iodine products unless a doctor advises it. Treatment of thyroid conditions and emergency use after radiation exposure: only as directed by a doctor or health authority.
Interactions
Iodine can change how antithyroid medicines (such as Carbimazole and Methimazole) and Levothyroxine work. Taking it with Lithium may increase the risk of an underactive thyroid. Amiodarone already contains a large amount of iodine. Potassium Iodide with ACE inhibitors, ARBs or potassium-sparing diuretics may raise blood potassium. Tell your doctor if you have thyroid disease before using any iodine supplement.
Contraindications
- Allergy or sensitivity to iodine.
- Overactive thyroid, unless a doctor advises it.
- Dermatitis herpetiformis or hypocomplementaemic vasculitis (rare conditions that iodine can worsen).
Side Effects
At normal supplement doses side effects are uncommon. Some people notice a metallic taste, stomach upset or diarrhoea. Too much iodine over time can cause thyroid problems.
Get urgent medical help if you have:
- Swelling of the face, lips or throat, difficulty breathing, or a severe rash.
- Fever with joint pain or swollen glands.
- A fast or irregular heartbeat, shaking, sweating and weight loss (signs of an overactive thyroid).
Pregnancy and Lactation
Iodine is important in pregnancy and breastfeeding, and a supplement providing about 150 mcg a day is often recommended. Do not take more than advised, as too much can affect the baby’s thyroid. Talk to your doctor if you have thyroid disease.
Precautions and Warnings
Use with care if you have thyroid disease, a thyroid nodule or goitre, or kidney disease, and in older people. Check all your supplements so that you do not take iodine from several products at once. Do not use iodine antiseptic solutions by mouth.
Overdose
A large amount can cause a burning feeling in the mouth and throat, stomach pain, vomiting and diarrhoea. Long-term high intake can cause an overactive or underactive thyroid. Seek medical help.
Therapeutic Class
Trace mineral (dietary supplement).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.