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

Potassium iodide 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.

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

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

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 potassium iodide 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, potassium iodide 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 potassium iodide.

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

Potassium iodide 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.

Usual Adult Dose for Cough:

300 to 600 mg diluted in a glass of water, fruit juice or milk orally 3 to 4 times a day

Comments:
-This drug should be used no longer than necessary to produce desired effect.

Uses: As an expectorant in the symptomatic treatment of chronic pulmonary diseases where tenacious mucus complicates the problem, including bronchial asthma, bronchitis and pulmonary emphysema.

Usual Adult Dose for Radiation Emergency:

130 mg orally once

Comments:
-In the event of a nuclear radiation emergency, take as directed by public officials; take first dose as soon as possible.
-Repeat doses may be needed in the event of prolonged exposure; since each dose provides up to 24 hours protection, repeat doses should be taken no sooner than 24 hours after prior dose.

Use: As a thyroid blocking agent during a nuclear radiation emergency.

Usual Pediatric Dose for Radiation Emergency:

Birth to 1 month: 16.25 mg orally once
Over 1 month to 3 years: 32.5 mg orally once
Over 3 months to 12 years: 65 mg orally once
Over 12 years; weight less than 150 pounds (68.18 kg): 65 mg orally once
Over 12 years; weight 150 pounds (68.18 kg) or greater: 130 mg orally once

Comments:
-In the event of a nuclear radiation emergency, take as directed by public officials; take first dose as soon as possible.
-Repeat doses may be needed in the event of prolonged exposure; since each dose provides up to 24 hours protection, repeat doses should be taken no sooner than 24 hours after prior dose.

Use: As a thyroid blocking agent during a nuclear radiation emergency.

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

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

• thyroid nodules and heart problems;

• dermatitis herpetiformis (Duhring disease, itchy skin rash common with celiac disease); or

• inflammation of the small blood vessels (hypocomplementemic urticarial vasculitis, or HUV) that causes episodes of hives, itching, burning, and painful skin sores.

Tell your doctor if you have ever had:

• a thyroid disorder;

• Addison's disease (an adrenal gland disorder);

• heart disease;

• tuberculosis;

• bronchitis;

• kidney disease; or

• myotonia congenita (a genetic muscle disorder).

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

Potassium iodide 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 potassium iodide 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.

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.

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

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

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.

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

• fever, tiredness;

• swelling in your neck or throat (enlarged thyroid, or goiter);

• chest pain, irregular heartbeats;

• numbness, tingling, pain, weakness, or swelling in your hands or feet;

• a weak or heavy feeling in your legs; or

• bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds.

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 potassium iodide may include:

• swelling or tenderness in your lower jaw;

• rash; or

• nausea, vomiting, diarrhea, upset stomach, or stomach pain.

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.

Tell your doctor about all your other medicines, especially:

• lithium;

• a diuretic or "water pill";

• an "ACE inhibitor" heart or blood pressure medicine--benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, trandolapril; or

• medication to treat overactive thyroid--methimazole, propylthiouracil (PTU), radioactive iodine.

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