Preoperatively to reduce vascularity of thyroid gland prior to thyroidectomy; usually used in conjunction with other antithyroid agents (e.g., propylthiouracil) and/or propranolol. For preparation of patients with Graves’ disease for surgery, potassium iodide and propranolol may be preferred regimen.
Management of thyrotoxic crisis (by preventing intrathyroid iodine accumulation); usually used in conjunction with other antithyroid agents (e.g., propylthiouracil) and/or propranolol.
May be useful for treatment of persistent or recurrent hyperthyroidism in patients with Graves’ disease after surgery or treatment with radioactive iodine.
Radiation Emergency
Blockage of thyroidal uptake of radioactive isotopes of iodine (e.g.,131I) that may be accidentally released into the environment (e.g., from a nuclear power plant), thus minimizing the risk of radiation-induced thyroid neoplasms. Has no impact on uptake of other radioactive materials and does not provide protection against external irradiation of any kind.
Used as an adjunct to other protective measures (e.g., evacuation, sheltering, assurance of uncontaminated milk and food). Neonates, children, pregnant or lactating women, and individuals who are unable to tolerate potassium iodide should be given priority with regard to these other protective measures.
The US government stockpiles potassium iodide tablets for emergency use, and the decision to distribute and use the drug resides with state and/or local public health authorities. (See Advice to Patients.)
Sporotrichosis
Has been used with good results in the treatment of cutaneous sporotrichosis† (localized to the skin; also known as fixed cutaneous or plaque sporotrichosis) and lymphocutaneous sporotrichosis† (involves skin, subcutaneous tissues, regional lymphatics) caused by Sporothrix schenckii. Oral itraconazole generally considered drug of choice for treatment of these conditions; potassium iodide considered alternative therapy because of problems with long-term compliance (i.e., numerous adverse effects, lack of solid oral dosage form).
Not effective in the treatment of extracutaneous (pulmonary, osteoarticular, meningeal) sporotrichosis† or disseminated sporotrichosis†; IV amphotericin B or oral itraconazole considered drugs of choice for these forms of sporotrichosis.
Cough
Has been used as an expectorant in the symptomatic management of conditions such as chronic bronchitis, bronchiectasis, bronchial asthma, and pulmonary emphysema; however, efficacy not established, and the drug generally has been replaced by more effective and safer expectorants.
Dosage and Administration
Administration
Oral Administration
Administer orally. To minimize GI irritation, administer after meals and at bedtime with food or milk.
Administer saturated (1-g/mL) oral solution in a large quantity (240 mL) of water, fruit juice, milk, formula, or broth. Administer 65-mg/mL oral solution undiluted using the dropper provided by the manufacturer. Dilute strong iodine solution with water or juice.
For administration in infants and small children during a radiation emergency, tablets may be pulverized, mixed with water and a drink, and administered as an oral solution; the best beverages to disguise the salty taste of potassium iodide are raspberry syrup (best), low-fat chocolate milk, orange juice, and flat soda (i.e., cola). To prepare an oral solution, place one tablet (containing 130 or 65 mg of potassium iodide) in a small bowl and pulverize tablet using a metal spoon. Then add 4 teaspoonsful (20 mL) of water to the powder and mix until powder dissolves. Next, add 4 teaspoonsful (20 mL) of the selected drink and mix. Using a 130-mg tablet results in a solution that contains 16.25 mg of potassium iodide per teaspoonful (5 mL). Using a 65-mg tablet results in a solution that contains 8.125 mg of potassium iodide per teaspoonful (5 mL).
During a radiation emergency, administer potassium iodide before or immediately coincident with passage of the radioactive cloud for optimal protection against inhaled radioiodines; administration 3–4 hours after exposure may still provide substantial protection.
Dosage
Available as potassium iodide; dosage expressed in terms of the salt. Potassium iodide also is available in fixed combination with iodine (i.e., strong iodine solution).
Pediatric Patients
Hyperthyroidism
Graves’ Disease
Oral
Neonates: 1 drop of strong iodine solution every 8 hours suggested by some clinicians.
Reduction of Thyroid Gland Vascularity in Preparation for Thyroidectomy
Administer only after achieving euthyroidism with other antithyroid agents (e.g., propylthiouracil).
Oral
Children: Usually, 50–250 mg (approximately 1–5 drops of a 1-g/mL solution) 3 times daily for 10–14 days before surgery.
Radiation Emergency
Oral
Recommended dosages vary by age and/or weight (see Table 1).
Table 1. Recommended Dosages of Potassium Iodide (i.e., Iosat®, ThyroSafe®, ThyroShield®) for Self-medication Before, During, or Immediately Following a Radiation Emergency in Pediatric Patients
Age
Predicted Thyroid Exposure
Potassium Iodide Dosage
Birth to 1 month
≥5 centigrays (cGy)
One 16-mg dose
>1 month to 3 years
≥5 cGy
32 mg once daily
>3–12 years
≥5 cGy
65 mg once daily
>12–18 years weighing <68.2 kg (150 lbs)
≥5 cGy
65 mg once daily
>12–18 years weighing ≥68.2 kg (150 lbs)
≥5 cGy
130 mg once daily
In neonates (birth to 1 month of age), avoid repeat administration to minimize risk of hypothyroidism during period of critical brain development. Monitor for hypothyroidism by measuring TSH and, if indicated, free thyroxine (T4) concentrations; institute thyroid replacement therapy if hypothyroidism occurs.
In other pediatric patients (infants, children, and adolescents), administer once daily (every 24 hours) until risk of substantial exposure to radioiodines (either by inhalation or ingestion) no longer exists.
Sporotrichosis
Cutaneous or Lymphocutaneous Sporotrichosis
Oral
Initially, 250 mg (approximately 5 drops of a 1-g/mL solution) 3 times daily. Gradually increase dosage as tolerated to a maximum of 1.25–2 g (approximately 25–40 drops of a 1-g/mL solution) 3 times daily. (See Pediatric Use under Cautions.)†
Usual duration of therapy is 3–6 months.†
Cough
Oral
Children: Usually, 60–250 mg 4 times daily. (See Pediatric Use under Cautions.)
Adults
Hyperthyroidism
Reduction of Thyroid Gland Vascularity in Preparation for Thyroidectomy
Administer only after achieving euthyroidism with other antithyroid agents (e.g., propylthiouracil).
Oral
Usually, 50–250 mg (approximately 1–5 drops of a 1-g/mL solution) 3 times daily for 10–14 days before surgery. Alternatively, 0.1–0.3 mL (approximately 3–5 drops) of strong iodine solution 3 times daily for 10–14 days before surgery.
Thyrotoxic Crisis
Administer initial dose ≥1 hour after initial dose of propylthiouracil or methimazole.
Oral
Dosage used preoperatively usually is adequate. (See Adults: Reduction of Thyroid Gland Vascularity in Preparation for Thyroidectomy under Dosage and Administration.)
Some clinicians recommend 500 mg every 4 hours (approximately 10 drops of a 1-g/mL solution). Alternatively, 1 mL of strong iodine solution 3 times daily has been suggested.
Radiation Emergency
Oral
Recommended dosages vary by age, predicted thyroid exposure, and pregnancy and lactation status (see Table 2).
Table 2. Recommended Dosages of Potassium Iodide (i.e., Iosat®, ThyroSafe®, ThyroShield®) for Self-medication Before, During, or Immediately Following a Radiation Emergency in Adults
Patient Group
Predicted Thyroid Exposure
Potassium Iodide Dosage
Pregnant or lactating women
≥5 cGy
One 130-mg dose
>18–40 years of age
≥10 cGy
130 mg once daily
>40 years of age
≥500 cGy
130 mg once daily
In pregnant women, generally avoid repeat administration because of risk of blocking fetal thyroid function; the risks versus benefits of repeat administration in pregnant women depend on the probability of continued radioiodine exposure. In lactating women, avoid repeat administration except during continuing severe contamination.
In patients >18 years of age, administer once daily (every 24 hours) until risk of substantial exposure to radioiodines (either by inhalation or ingestion) no longer exists.
Sporotrichosis
Cutaneous or Lymphocutaneous Sporotrichosis
Oral
Initially, 250 mg (approximately 5 drops of a 1-g/mL solution) 3 times daily. Gradually increase dosage as tolerated to a maximum of 2–2.5 g (approximately 40–50 drops of a 1-g/mL solution) 3 times daily.†
Usual duration of therapy is 3–6 months.†
Cough
Oral
Usually, 300–650 mg 3 or 4 times daily.
Prescribing Limits
Pediatric Patients
Radiation Emergency
Oral
Neonates (birth to 1 month of age): Maximum one dose. (See Pediatric Patients: Radiation Emergency under Dosage and Administration.)
Pediatric patients >1 month to 18 years of age: Maximum one dose every 24 hours. (See Pediatric Patients: Radiation Emergency under Dosage and Administration.)
Sporotrichosis
Cutaneous or Lymphocutaneous Sporotrichosis
Oral
Children: Maximum 1.25–2 g (approximately 25–40 drops of a 1-g/mL solution) 3 times daily. (See Pediatric Use under Cautions.)†
Adults
Radiation Emergency
Oral
Pregnant and lactating women: Maximum one dose except during continuing severe contamination. (See Adults: Radiation Emergency under Dosage and Administration.)
Adults >18 years of age: Maximum 1 dose every 24 hours. (See Adults: Radiation Emergency under Dosage and Administration.)
Sporotrichosis
Cutaneous or Lymphocutaneous Sporotrichosis
Oral
Maximum 2–2.5 g (approximately 40–50 drops of a 1-g/mL solution) 3 times daily.†
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