potassium iodide

Potassium iodide is an oral medication that has been used for a long time as an expectorant to break up mucus and make it easier to cough up and eliminate phlegm.

What does potassium iodide do for the body?

Potassium iodide is also used to inhibit thyroid hormone production in patients with an overactive thyroid (hyperthyroidism) and thyrotoxicosis. With the development of nuclear power, potassium iodide has been used to prevent the thyroid gland from absorbing harmful radioactive iodine in a radiation emergency.

Iodine, the active component of potassium iodide, is a trace mineral used by the thyroid gland to produce thyroid hormones which have many important functions including the regulation of metabolic rate, temperature regulation, growth, and development. Iodine is used to decrease the secretion and synthesis of thyroid hormone in patients with hyperthyroidism. Iodine also increases respiratory secretion and reduces its viscosity, making it easier to cough up phlegm.

In a nuclear radiation emergency, usually nuclear power plant accidents, radioactive iodine can be absorbed by the thyroid gland, which increases the risk for thyroid cancer years after exposure, especially in infants, children, and young adults. Potassium iodide delivers a high quantity of iodine which saturates the thyroid gland and prevents it from absorbing the harmful radioactive iodine from the environment.

The uses of potassium iodide include:

Adult:

• Radiation emergency
• Expectorant
• Thyroid storm (thyrotoxic crisis)
• Preoperative thyroidectomy
• Cystic fibrosis (adjunct)
• Chronic sinusitis (adjunct)

Pediatric:

• Radiation emergency
• Expectorant
• Neonatal Graves’ disease

• Do not use potassium iodide in patients with iodine sensitivity (allergy to radiocontrast media, contact dermatitis from iodine-containing antibacterial drugs, or allergy to seafood should not be considered evidence of potassium iodide allergy).
• Do not use potassium iodide in patients with hyperthyroidism or those taking medications that alter thyroid function.
• Avoid using in patients with kidney failure because of the presence of potassium.
• Avoid concurrent use with potassium-sparing diuretics or angiotensin-converting-enzyme inhibitors, it can lead to hyperkalemia.
• Avoid use in patients with respiratory failure.
• Use with caution in patients with tuberculosis.
• Avoid use in immunocompromised patients, potassium iodide can affect the immune system.
• Prescription for radiation exposure should be made only upon order from authorities.
• Avoid repeat dosing of potassium iodide in newborns and pregnant and breastfeeding women and give priority to these individuals for evacuation during a radiation emergency. Although, the benefits of short-term use of potassium iodide to block uptake of radioactive iodine by the thyroid gland far exceed its chances of side effects.
• Iodine poisoning (iodism) can cause symptoms such as metallic taste, sore mouth and severe headache.

Common side effects of potassium iodide include:

• Nausea
• Vomiting
• Diarrhea
• Stomach pain
• Gastrointestinal irritation or bleeding
• Metallic taste
• Iodide poisoning syndrome (iodism) with prolonged use causes symptoms such as:
  • Soreness of teeth and gums
  • Severe headache
  • Watering of eyes (lacrimation)
  • Blood vessel dilation in the eye membrane (conjunctival hyperemia)
  • Blurred vision
  • Excessive salivation (sialorrhea)
  • Nasal discharge (rhinorrhea)
• Underactive thyroid (hypothyroidism)
• Severe hypothyroidism (myxedema)
• Overactive thyroid (hyperthyroidism)
• Thyroid enlargement (goiter)
• Benign tumor of the thyroid (thyroid adenoma)
• Swelling of neck and throat
• Swelling of lymph nodes
• Swelling of salivary glands
• Numbness and tingling (paresthesia)
• Irregular heart rhythm (arrhythmia)
• Allergic skin reactions including:
  • Skin rash
  • Hives (urticaria)
  • Ioderma, a type of skin eruption
  • Itching
• Hypersensitivity reactions including:
  • Fever
  • Jaundice
  • High eosinophil count (eosinophilia)
  • Swelling under the skin and mucus membrane (angioedema)
  • Bronchospasm

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Tablet

• 65 mg
• 130 mg

Oral Solution

• 65 mg/mL
• 325 mg/5mL

Oral Solution (Concentrated)

• 1 g/mL

Adult:

Radiation Emergency

• Indicated during environmental radiation emergency to block uptake of radioactive iodine isotopes in thyroid and reduce risk of thyroid cancer
• 130 mg orally once daily; not to exceed 1 dose/24 hours
• Ideally initiate 1-48 hours prior to exposure
• Continue daily dose until exposure risk has passed and/or until other measures (e.g., evacuation, sheltering, control of the food and milk supply) have been successfully implemented

Risk reduction with acute exposure

• KI initiated shortly before or immediately after acute exposure: 90-99% risk reduction
• KI initiated within 3-4 hours after acute exposure: 50% risk reduction
• KI initiated up to 12 hours after acute exposure: limited benefit may be achieved

Expectorant

• SSKI: 300-600 mg orally every 6-8 hours

Thyrotoxic Crisis

• 250-500 mg (5-10 drops of 1 g/mL) orally every 4-6 hours

Preoperative Thyroidectomy

• 50-250 mg (1-5 drops of 1 g/mL) orally every 8 hours for 10-14 days

Other Indications and Uses

• Cystic fibrosis, chronic sinusitis (adjunct)

Pediatric:

Radiation Emergency

• Indicted during environmental radiation emergency to block uptake of radioactive iodine isotopes in thyroid and reduce risk of thyroid cancer
• Infants below 1 month: 16.25 mg orally once daily; not to exceed 1 dose/24 hours
• Children 1 month-3 years: 32.5 mg orally once daily; not to exceed 1 dose/24 hours
• Children 3-13 years: 65 mg orally once daily; not to exceed 1 dose/24 hours
• Children above 13 years or adolescents weighing more than 70 kg (154 lb.): 130 mg orally once daily; not to exceed 1 dose/24 hours
• Ideally initiate 1-48 hours prior to exposure
• Continue daily dose until exposure risk has passed and/or until other measures (e.g., evacuation, sheltering, control of the food and milk supply) have been successfully implemented

Risk reduction with acute exposure

• KI initiated shortly before or immediately after acute exposure: 90-99% risk reduction
• KI initiated within 3-4 hours after acute exposure: 50% risk reduction
• KI initiated up to 12 hours after acute exposure: limited benefit may be achieved
• Neonatal Graves’ disease
  • SSKI: 1 drop orally every 8 hours
• Expectorant
  • SSKI: 60-250 mg orally every 6 hours

Overdose

• Acute overdose from potassium iodide is unlikely.
• Prolonged use can lead to iodine poisoning (iodism) with symptoms that include metallic taste, sore mouth, and severe headache, and can result in goiter and impaired thyroid function.
• Prolonged use can also lead to high potassium levels in the blood (hyperkalemia). Treatment includes discontinuation of the drug and symptomatic and supportive care.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Severe interactions of potassium iodide include:
  • sodium iodide I-131
• Potassium iodide has no known serious interactions with other drugs.
• Potassium iodide has moderate interactions with at least 107 different drugs.
• Potassium iodide has no known mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

• Use of potassium iodide during pregnancy can cause fetal harm. Restrict use in pregnant women to only life-threatening emergencies.
• It is recommended that pregnant women and newborns should be given priority for evacuation, safe shelter, and safe food/milk during a radiation emergency to avoid repeat dosing of potassium iodide, because of the increased risk for thyroid suppression in the fetus and newborn.
• Potassium iodide is excreted into breast milk. Use with caution in nursing mothers and avoid treatment for longer than 1 day. If longer treatment is required, consult with your physician to decide if it is required to stop breastfeeding.

• Take potassium iodide exactly as prescribed.
• Do not take potassium iodide unless you are instructed by public health or emergency response officials or a healthcare provider.
• When used for radiation emergency, potassium iodide:
  • Protects only against radioactive iodine and does not protect against other types of radiation.
  • Protects only the thyroid, it does not protect other parts of the body.
  • Is most effective only if taken within 24 hours before or 4 hours after exposure.
  • Is only useful to prevent absorption of radioactive iodine by the thyroid and it cannot reverse damage already done to the thyroid.
  • May not give a person 100% protection from radioactive iodine.
• Store potassium iodide safely out of reach of children.
• In case of overdose, contact your physician or Poison Control.