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Potassium Iodide and Iodine

Pronunciation

(poe TASS ee um EYE oh dide & EYE oh dine)

Index Terms

  • Iodine and Potassium Iodide
  • Lugol's Solution
  • Potassium Iodide/Iodine
  • Strong Iodine Solution

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, External:

Generic: Potassium iodide 10% and iodine 5% (8 mL)

Solution, Oral:

Generic: Potassium iodide 10% and iodine 5% (14 mL, 473 mL)

Tincture, External:

Generic: Potassium iodide 5% and iodine 7% (30 mL, 480 mL)

Pharmacologic Category

  • Antiseptic, Topical
  • Antithyroid Agent

Pharmacology

In hyperthyroidism, iodine temporarily inhibits thyroid hormone synthesis and secretion into the circulation; use also decreases thyroid gland size and vascularity. Serum T4 and T3 concentrations can be reduced for several weeks with use but effect will not be maintained.

Following radioactive iodine exposure, potassium iodide blocks uptake of radioiodine by the thyroid, reducing the risk of thyroid cancer.

Onset of Action

Hyperthyroidism: 24-48 hours; Peak effect: 10-15 days after continuous therapy

Use: Labeled Indications

Topical antiseptic

Use: Unlabeled

Reduce thyroid vascularity prior to thyroidectomy and management of thyrotoxic crisis; block thyroidal uptake of radioactive isotopes of iodine in a radiation emergency or after therapeutic/diagnostic use of radioactive iodine

Contraindications

Hypersensitivity to iodine or any component of the formulation; iodine-induced goiter; dermatitis herpetiformis; hypocomplementemic vasculitis; nodular thyroid disease with heart disease

Dosing: Adult

Antiseptic: Topical: Apply directly to area(s) requiring antiseptic.

RDA: 150 mcg (iodine)

Preparation for thyroidectomy (off-label use): Oral: 5-7 drops (0.25-0.35 mL) 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)

Thyrotoxic crisis (off-label use): Oral: 4-8 drops every 6-8 hours; begin administration ≥1 hour following the initial dose of either propylthiouracil or methimazole (Nayak, 2006)

Thyroid gland protection during radiopharmaceutical use (off-label use): Oral: 20 drops 3 times daily has been recommended (Bexxar® prescribing information, 2012)

Note: Initiate 1-48 hours prior to radiopharmaceutical exposure and continue after radiopharmaceutical administration until risk of exposure has diminished (treatment initiation time and duration is dependent on the radiopharmaceutical agent used, consult specific protocol or labeling.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Thyrotoxic crisis (off-label use): Oral: 4-8 drops 3 times daily; begin therapy preferably 2 hours following the initial dose of propylthiouracil or alternatively, methimazole (Eyal, 2008)

Dosing: Renal Impairment

No dosage adjustment provided in manufacturer’s labeling.

Dosing: Hepatic Impairment

No dosage adjustment provided in manufacturer’s labeling.

Administration

Apply topically directly to area(s) requiring antiseptic. Has also been used orally (off-label route).

Storage

Store at room temperature of 15°C to 30°C (59°F to 86°F). Protect from light and keep container tightly closed.

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, myxedema

Central nervous system: Confusion, fatigue, metallic taste, numbness, tingling sensation

Dermatologic: Skin rash

Endocrine & metabolic: Goiter, hyperthyroidism, hypothyroidism

Gastrointestinal: Diarrhea, enlargement of salivary glands, gastric distress, gastrointestinal hemorrhage, nausea, salivary gland disease (tenderness), stomach pain, vomiting

Hematologic & oncologic: Adenopathy, thyroid adenoma

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

Neuromuscular & skeletal: Arthralgia, weakness

Respiratory: Pharyngeal edema

Miscellaneous: Drug overdose (with prolonged treatment/high doses), fever, iodism

Warnings/Precautions

Concerns related to adverse effects:

• Hypothyroidism: Prolonged use can lead to hypothyroidism.

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

Disease-related concerns:

• Adrenal insufficiency: Use with caution in patients with Addison's 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.

• Thyroid disease: Use with caution in patients with a history of hyperthyroidism; use is contraindicated in nodular thyroid conditions with heart disease.

• 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.

Monitoring Parameters

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

Pregnancy Risk Factor

D (potassium iodide)

Pregnancy Considerations

Iodide crosses the placenta (may cause hypothyroidism and goiter in fetus/newborn). 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. Repeat dosing should be avoided if possible. Refer to Iodine 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 skin rash. Have patient report immediately to prescriber severe abdominal pain, severe nausea, severe vomiting, or diarrhea (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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