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Generic name: potassium iodidepoe-TAH-see-um-EYE-oh-dide ]
Brand names: iOSAT, SSKI (saturated), ThyroSafe, ThyroShield
Drug classes: Antithyroid agents, Expectorants

Medically reviewed by on Aug 14, 2023. Written by Cerner Multum.

What is ThyroShield?

ThyroShield is used to thin mucus and loosen congestion in the chest and throat. This medicine is used in people with breathing problems that can be complicated by thick mucus, such as asthma, chronic bronchitis, or emphysema.

ThyroShield is used during a nuclear radiation emergency to block radioactive iodine from entering your thyroid gland. For this purpose, the medicine is usually taken only once or twice.

ThyroShield may also be used for purposes not listed in this medication guide.

ThyroShield side effects

Get emergency medical help if you have signs of an allergic reaction: hives, rash; fever, swollen glands, joint pain; wheezing, difficult breathing, trouble swallowing; swelling of your face, lips, tongue, or throat.

ThyroShield may cause serious side effects. Stop using ThyroShield and call your doctor at once if you have:

High doses or long-term use of potassium iodide may cause iodine poisoning. Tell your doctor if you have symptoms such as burning in your mouth or throat, a metallic taste, tooth or gum pain, drooling, severe headache, cold symptoms (stuffy nose, sneezing) eye irritation, or severe skin rash.

Common side effects of ThyroShield may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Before taking this medicine

You should not use ThyroShield if you ar allergic to iodide or iodine.

You may not be able to use ThyroShield for exposure to nuclear radiation if you have:

Tell your doctor if you have ever had:

ThyroShield is used in children only during a nuclear radiation emergency. Do not give ThyroShield to a child without medical advice.

ThyroShield can cause thyroid problems in both mother and baby when used during pregnancy. However, the benefit of taking this medicine to protect your thyroid from nuclear radiation exposure far outweighs any risks of thyroid harm.

Any pregnant or breastfeeding woman or infant who takes ThyroShield should have their thyroid function checked after using this medicine. Seek medical care as soon as possible.

If you are breastfeeding, tell your doctor if you notice a skin rash, muscle weakness, yellowed skin, breathing problems, feeding problems, or unusual crying in the nursing baby.

How should I take ThyroShield?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take with food or milk if ThyroShield upsets your stomach.

Measure liquid medicine with the supplied measuring device (not a kitchen spoon). Mix the liquid with water, fruit juice, or milk before taking.

For thinning mucus in the chest and throat, ThyroShield is usually taken 3 to 4 times each day. Follow your doctor's dosing instructions very carefully. Use this medicine only as long as needed to get the best results.

For thyroid protection after nuclear radiation exposure, take the medicine as soon as possible after instructed by public officials. If you are told to take a second dose, wait at least 24 hours after you took the first dose. Use only as many doses as public officials tell you. Taking more of this medicine will not make it work better or faster, and may increase the risk of side effects.

Follow all directions when giving this medicine to a child during a nuclear emergency. Doses are based on weight in children and teenagers.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using ThyroShield.

Store at room temperature away from moisture, heat, and light.

ThyroShield liquid may crystallize if it gets cold. To clear the crystals, shake the liquid or allow it to reach room temperature. Do not use if the liquid has turned brown or yellow. Call your pharmacist for new medicine.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking ThyroShield?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect ThyroShield?

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may affect ThyroShield, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.