WHY is this medicine prescribed?
Potassium iodide is used to protect the thyroid gland from taking in radioactive iodine that may be released during a nuclear radiation emergency. Radioactive iodine can damage the thyroid gland. You should only take potassium iodide if there is a nuclear radiation emergency and public officials tell you that you should take it. Potassium iodide is in a class of medications called anti-thyroid medications. It works by blocking radioactive iodine from entering the thyroid gland.
Potassium iodide can protect you from the effects of radioactive iodine that may be released during a nuclear radiation emergency, but will not protect you from other dangerous substances that may be released during the emergency. Public officials may tell you to do other things to protect yourself during the emergency. Follow all of these directions carefully.
HOW should this medicine be used?
Potassium iodide comes as a liquid and a tablet to take by mouth. It is usually taken once a day for as many days as public officials say it is needed. Take potassium iodide at around the same time every day. If you are told to take potassium iodide during a nuclear radiation emergency, you should not take it more often than once every 24 hours. Follow the directions on the package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take potassium iodide exactly as directed. Do not take more or less of it than directed on the package label. Taking potassium iodide more often will not give you more protection during the emergency, and will increase the risk that you may experience side effects.
The dose of potassium iodide you should take or give to your child depends on your age or your child's age. If potassium iodide is taken by a teenager between the ages of 12 to 18 years, the dose also depend on the teenager's weight. Check the package label to see what dose you should take yourself or give to your child. Ask your doctor, pharmacist, or public official if you have questions.
Potassium iodide tablets can be crushed and mixed with water and certain other liquids including low-fat white or chocolate milk, flat soda, orange juice, raspberry syrup, or infant formula so that they can be given to children or people who cannot swallow tablets. Check the package label to find out how to make this mixture and how much of this mixture you should take or give to your child. If you do make a mixture, store it in the refrigerator and use it within 7 days. Dispose of any unused mixture after 7 days.
Read the manufacturer's information for the patient carefully. Ask your doctor or pharmacist if you have any questions.
Are there OTHER USES for this medication?
Potassium iodide is also sometimes used to treat overactive thyroid gland and sporotrichosis (a skin infection caused by a fungus). Talk to your doctor about the risks of using this medication for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What SPECIAL PRECAUTIONS should I follow?
Before taking potassium iodide,
What SPECIAL DIETARY instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do IF I FORGET to take a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one and do not take 2 doses less than 24 hours apart.
What SIDE EFFECTS can this medicine cause?
Potassium iodide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
Some side effects can be serious. If you experience any of these symptoms, stop taking potassium iodide and call your doctor immediately:
Potassium iodide may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I do in case of OVERDOSE?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
What should I know about STORAGE and DISPOSAL of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom). Some bottles of potassium iodide may be safe to use after the expiration date stamped on the bottle; ask your doctor or pharmacist for more information.
Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.
Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location - one that is up and away and out of their sight and reach. http://www.upandaway.org
What OTHER INFORMATION should I know?
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to potassium iodide.
Ask your pharmacist any questions you have about potassium iodide.
Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.
This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.
The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.
AHFS® Patient Medication Information™ Copyright, 2025. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Selected Revisions: November 15, 2016.