Class: Antithyroid Agent
Dosage Forms. Tablet: 65 mg, 130 mg; Solution: 65 mg/mL, 1 g/mL
Common FDA Label Indication, Dosing, and Titration.
1. Prevention of thyroid dysfunction due to radiation exposure: Children, birth to 1 mo, 16.25 mg po daily; Children 1 mo to 3 y, 32.5 mg po daily; Children 3-12 y, 65 mg po daily; Children over 12 y but <150 pounds, 65 mg po daily; Children over 12 y and 150 pounds or greater and Adults: 130 mg po daily
1. Induction or involution of thyroid: 60-250 mg po tid × 10 d preoperatively to reduce vascularity of the gland prior to thyroidectomy
2. Graves disease (short-term reduction of thyroid hormone production prior to ablation or surgery): 50 mg po q8h
MOA. Iodine is needed for the production of thyroid hormones. In patients with disorders causing hyperthyroidism, iodide is administered to inhibit the release of thyroid hormones via direct effect on the thyroid gland and inhibits synthesis of thyroid hormones. Also attenuates effects of TSH mediated via cAMPb and decreases vascularity of thyroid gland. When administered before or promptly after radioactive iodine exposure, potassium iodide blocks or reduces accumulation of radioactive iodine in the thyroid gland.
Drug Characteristics: Potassium Iodide
Medication Safety Issues: Potassium Iodide
Drug Interactions: Potassium Iodide
Adverse Reactions: Potassium Iodide
Efficacy Monitoring Parameters. Thyroid function tests.
Toxicity Monitoring Parameters. Serum potassium, SCr, BUN, signs/symptoms of goiter, hypothyroidism, thyroid adenoma, allergic reaction, hyperkalemia.
Key Patient Counseling Points. To minimize GI irritation, administer with food. Take with 4 ounces of water. Other liquids can be used; dilution in chocolate milk can mask the taste. During a radiation emergency, understand the nature of the radiation hazard and the potential benefits and adverse effects of potassium iodide. Administer potassium iodide only as directed by public health authorities. Adhere to other emergency measures recommended by public health authorities.
Clinical Pearls. Potassium iodide has been used in the past as an expectorant and cough suppressant, which is absurd, given the risk of adverse effects associated with this treatment. Potassium iodide does cross into breast milk, but most guidelines consider it usually compatible with breast feeding.