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Potassium Iodide

Pronunciation

(poe TASS ee um EYE oh dide)

Index Terms

  • KI
  • Saturated Potassium Iodide Solution
  • Saturated Solution of Potassium Iodide

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Solution, Oral:

SSKI: 1 g/mL (30 mL, 237 mL)

ThyroShield: 65 mg/mL (30 mL [DSC]) [contains brilliant blue fcf (fd&c blue #1), fd&c red #40, methylparaben, propylene glycol, propylparaben, saccharin sodium; black raspberry flavor]

Tablet, Oral:

iOSAT: 130 mg [scored]

ThyroSafe: 65 mg [scored]

Brand Names: U.S.

  • iOSAT [OTC]
  • SSKI
  • ThyroSafe [OTC]
  • ThyroShield [OTC] [DSC]

Pharmacologic Category

  • Antidote
  • Antithyroid Agent
  • Expectorant

Pharmacology

Reduces viscosity of mucus by increasing respiratory tract secretions; inhibits secretion of thyroid hormone, fosters colloid accumulation in thyroid follicles. Following radioactive iodine exposure, potassium iodide blocks the uptake of radioactive iodine by the thyroid, reducing the risk of thyroid cancer.

Onset of Action

Hyperthyroidism: 24 to 48 hours (Nayak 2006); Peak effect: ~2 weeks after continuous therapy (Nayak 2006)

Duration of Action

Radioactive iodine exposure: Each dose has a duration of ~24 hours

Use: Labeled Indications

Antidote: Block thyroidal uptake of radioactive isotopes of iodine in a nuclear radiation emergency.

Expectorant: Expectorant for the symptomatic treatment of chronic pulmonary diseases complicated by mucous.

Contraindications

Hypersensitivity to iodide, iodine, or any component of the formulation; dermatitis herpetiformis; hypocomplementemic vasculitis, nodular thyroid condition with heart disease

Dosing: Adult

RDA for iodine: 150 mcg/day

Expectorant (SSKI): Oral: 300 to 600 mg (0.3 to 0.6 mL) 3 to 4 times daily

Antidote [thyroid block following nuclear radiation emergency (iOSAT, ThyroSafe, ThyroShield)]: Includes pregnant/lactating women: Oral: 130 mg once daily, continue for 10 to 14 days or as directed by public officials (until risk of exposure has passed or other measures are implemented)

Thyroidectomy preparation (off-label use): Oral: 50 to 100 mg (1 to 2 drops or 0.05 to 0.1 mL SSKI) 3 times daily; administer for 10 days before surgery; if not euthyroid prior to surgery, consider concurrent beta-blockade (eg, propranolol) in the immediate preoperative period to reduce the risk of thyroid storm (Bahn 2011)

Sporotrichosis (cutaneous, lymphocutaneous; off-label use) (SSKI): Oral: Initial: 5 drops 3 times daily; increase to 40 to 50 drops 3 times daily as tolerated until 2 to 4 weeks after lesions have resolved (usual duration 3 to 6 months) (Kauffman 2007)

Thyroid gland protection during radiopharmaceutical use (off-label use): Oral: Tablet: 130 mg once daily or Solution (SSKI): 4 drops 3 times daily (Bexxar prescribing information 2012). Note: Begin at 1 to 48 hours prior to exposure. Continue potassium iodide after radiopharmaceutical administration until risk of exposure has diminished (treatment duration and time of initiation is dependent on the radiopharmaceutical, consult specific protocol).

Thyrotoxic crisis/thyroid storm (off-label use): Oral: Note: Administer at least 1 hour after antithyroid drug administration: SSKI 250 mg (5 drops or 0.25 mL) every 6 hours (Bahn 2011)

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Antidote [thyroid block following nuclear radiation emergency (iOSAT, ThyroSafe, ThyroShield)]: Dosing should continue for 10 to 14 days or as directed by public officials (until risk of exposure has passed or other measures are implemented): Oral:

Infants ≤1 month: 16.25 mg once daily

Infants >1 month to Children ≤3 years: 32.5 mg once daily

Children >3 to ≤12 years: 65 mg once daily

Children >12 years and Adolescents weighing <68 kg: 65 mg once daily

Children >12 years and Adolescents weighing ≥68 kg: 130 mg once daily

Thyroidectomy preparation (off-label use): Oral: 150 to 350 mg (3 to 7 drops or 0.15 to 0.35 mL SSKI) 3 times daily; administer for 10 days before surgery; if not euthyroid prior to surgery, consider concurrent beta-blockade (eg, propranolol) in the immediate preoperative period to reduce the risk of thyroid storm (Bahn 2011)

Thyroid gland protection during radiopharmaceutical use (off-label use): Oral (Giammarile 2008, Olivier 2003):

Infants <5 kg: 16 mg once daily

Children 1 month to 3 years or 5 to 15 kg: 32 mg once daily

Children 3 to 13 years or 15 to 50 kg: 65 mg once daily

Children >13 years or >50 kg: 130 mg once daily

Note: Begin at 1 to 48 hours prior to exposure. Continue potassium iodide after radiopharmaceutical administration until risk of exposure has diminished (treatment duration and time of initiation is dependent on the radiopharmaceutical, consult specific protocol.

Thyrotoxic crisis/thyroid storm (off-label use): Oral: Note: Administer preferably 2 hours after antithyroid drug administration:

Infants: SSKI 100 mg (2 drops or 0.1 mL) 4 times daily (Eyal 2008)

Children: SSKI 250 mg (5 drops or 0.25 mL) 2 to 4 times daily (Eyal 2008)

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer’s labeling; use with caution.

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer’s labeling.

Extemporaneously Prepared

A 16.25 mg/5 mL oral solution may be made with tablets. Crush one 130 mg tablet and reduce to a fine powder. Add 20 mL of water and mix until powder is dissolved. Add an additional 20 mL of low-fat milk (white or chocolate), orange juice, flat soda, raspberry syrup, or infant formula. Stable for 7 days under refrigeration. Discard any unused portion.

To prepare an 8.125 mg/5 mL oral solution, crush one 65 mg tablet and reduce to a fine powder. Add 20 mL of water and mix until powder is dissolved. Add an additional 20 mL of low-fat milk (white or chocolate), orange juice, flat soda, raspberry syrup, or infant formula. Stable for 7 days under refrigeration. Discard any unused portion.

Administration

Oral:

SSKI: Dilute in a glassful of water, fruit juice, or milk. Administer with food or milk to decrease gastric irritation.

iOSAT, Thyrosafe, Thyroshield: Administer as soon as possible after instructed to do so by public officials. Do not take more than 1 dose in 24 hours. Tablets may be administered whole or crushed and then mixed with water, low fat milk (white or chocolate), orange juice, soda (flat), raspberry syrup, or infant formula. Raspberry syrup disguises the taste best; low-fat white milk or water do not hide the salty taste well) (AAP 2003). See Extemporaneously Prepared.

Storage

Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Protect from light. Keep tightly closed.

SSKI: If exposed to cold, crystallization may occur. Warm and shake to redissolve. If solution becomes brown/yellow, it should be discarded.

iOSAT, Thyrosafe: Keep dry and intact in foil.

Drug Interactions

ACE Inhibitors: Potassium Salts may enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Aliskiren: Potassium Salts may enhance the hyperkalemic effect of Aliskiren. Monitor therapy

Angiotensin II Receptor Blockers: Potassium Salts may enhance the hyperkalemic effect of Angiotensin II Receptor Blockers. Monitor therapy

Cardiac Glycosides: Antithyroid Agents may increase the serum concentration of Cardiac Glycosides. Monitor therapy

Eplerenone: May enhance the hyperkalemic effect of Potassium Salts. Management: This combination is contraindicated in patients receiving eplerenone for treatment of hypertension. Consider therapy modification

Heparin: May enhance the hyperkalemic effect of Potassium Salts. Monitor therapy

Heparin (Low Molecular Weight): May enhance the hyperkalemic effect of Potassium Salts. Monitor therapy

Lithium: Potassium Iodide may enhance the hypothyroid effect of Lithium. Monitor therapy

Nicorandil: May enhance the hyperkalemic effect of Potassium Salts. Monitor therapy

Potassium-Sparing Diuretics: Potassium Salts may enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Consider therapy modification

Sodium Iodide I131: Antithyroid Agents may diminish the therapeutic effect of Sodium Iodide I131. Management: Discontinue antithyroid therapy 3-4 days prior to sodium iodide I-131 administration. Avoid combination

Theophylline Derivatives: Antithyroid Agents may increase the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Antithyroid Agents may diminish the anticoagulant effect of Vitamin K Antagonists. Consider therapy modification

Test Interactions

Iodide may alter thyroid function tests.

Adverse Reactions

Frequency not defined.

Cardiovascular: Cardiac arrhythmia

Central nervous system: Confusion, fatigue, fever, numbness, tingling sensation

Dermatologic: Skin rash, urticaria

Endocrine & metabolic: Goiter, hyperthyroidism (prolonged use), hypothyroidism (prolonged use), myxedema

Gastrointestinal: Diarrhea, enlargement of salivary glands, gastric distress, gastrointestinal hemorrhage, metallic taste, nausea, stomach pain, vomiting

Hematologic & oncologic: Lymphedema, thyroid adenoma

Hypersensitivity: Hypersensitivity reaction (angioedema, cutaneous and mucosal hemorrhage, serum sickness-like symptoms)

Neuromuscular & skeletal: Weakness

Respiratory: Dyspnea, wheezing

Miscellaneous: Iodine poisoning (with prolonged treatment/high doses)

Warnings/Precautions

Concerns related to adverse effects:

• Hypersensitivity: Iodide hypersensitivity may occur, manifesting as angioedema, cutaneous/mucosal hemorrhage, and serum sickness-like symptoms (fever, arthralgia, lymph node enlargement, and eosinophilia).

• Skin reactions: Can cause acne flare-ups and/or dermatitis.

• Thyroid adverse effects: Prolonged use may lead to hypothyroidism. Iodide may cause underactive or overactive thyroid; thyroid enlargement may also occur. Use with caution in patients with a history of hyperthyroidism; use is contraindicated in patients with nodular thyroid condition (goiter) with heart disease. Iodism or chronic iodide poisoning may occur with high doses or prolonged treatment; symptoms include burning of mouth/throat, sore teeth/gums, severe headache, metallic taste, eye irritation/eye lid swelling, increased salivation, acneform skin lesions, and (rarely) severe skin lesions; withhold potassium iodide treatment and manage with supportive care.

Disease-related concerns:

• Adrenal insufficiency: Use with caution in patients with Addison disease.

• Bronchitis: Use with caution in patients with acute bronchitis.

• Cardiac disease: Use with caution in patients with cardiac disease.

• Myotonia congenita: Use with caution in patients with myotonia congenita.

• Renal impairment: Use with caution in patients with renal impairment

• Tuberculosis: Use with caution in patients with tuberculosis.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Pediatric: In a nuclear radiation emergency, infants and children are more likely to experience thyroid damage. Neonates <1 month are at higher risk for hypothyroidism with potassium iodide use; evaluate thyroid function if repeat dosing is required in this patient population.

Other warnings/precautions:

• Appropriate use: For thyroid gland protection (radiopharmaceutical use), potassium iodide must be administered prior to receiving radiopharmaceuticals that require thyroid gland protection. For nuclear radiation emergency, take only when instructed by public health officials; do not take more or more often than instructed; follow other emergency measures recommended by officials.

Monitoring Parameters

Thyroid function tests, signs/symptoms of hyperthyroidism; thyroid function should be monitored in pregnant or breast-feeding women, neonates, and young infants if repeat doses are required following radioactive iodine exposure

Pregnancy Risk Factor

D

Pregnancy Considerations

Iodide crosses the placenta (may cause hypothyroidism and goiter in fetus/newborn). Use as an expectorant during pregnancy is contraindicated by the AAP (AAP 1976). Use for protection against thyroid cancer secondary to radioactive iodine exposure is considered acceptable based upon risk:benefit, keeping in mind the dose and duration (AAP 2003). In general, medications used as antidotes should take into consideration the health and prognosis of the mother; antidotes should be administered to pregnant women if there is a clear indication for use and should not be withheld because of fears of teratogenicity (Bailey, 2003). Pregnant women should take as instructed by public officials and contact their physician. Repeat dosing should be avoided if possible (AAP 2003). Refer to Iodine monograph for additional information.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience nausea, vomiting, abdominal pain, or diarrhea. Have patient report immediately to prescriber dysphagia, difficulty speaking, wheezing, cough, shortness of breath, arrhythmia, angina, joint pain, swelling of neck, swelling of arms or legs, black, tarry, or bloody stools, vomiting blood, burning or numbness feeling, severe loss of strength and energy, confusion, severe headache, metallic taste, teeth or gingival changes, burning of mouth or throat, eye irritation, eyelid edema, drooling, or skin irritation (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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