Iodine (Potassium Iodide)

Indications

Iodine (Potassium Iodide) is used for: Grave's disease, Iodine deficiency disorders, Wound and ulcer cleansing, hyperthyroidism, Superficial wounds, Thyroid storm .

Adult Dose

Oral Preoperative reduction of vascularity of the thyroid gland Adult: As potassium iodide: 50-250 mg (approx 1-5 drops of a solution containing 1 g/ml) tid for 10-14 days before surgery. Radiation protection against radioactive iodine Adult: As potassium iodide: 100-150 mg 24 hr before procedure and daily for up to 10 days after procedure. Thyrotoxicosis Adult: 500 mg every 4 hr. Given 1 hr after an antithyroid agent. Iodine deficiency disorders Adult: As iodised oil: 400 mg iodine once yrly. Pregnant patient: 200 mg iodine as a single dose. Moderate to severe: 300-480 mg iodine each yr or 100-300 mg iodine every 6 mth and for at least 1 yr postpartum. Intramuscular Iodine deficiency disorders Adult: As iodised oil: Up to 45 yr: 380 mg iodine, as single IM doses to provide adequate protection from iodine deficiency for up to 3 yr. Pregnant patient: Moderate to severe: 480 mg iodine each yr.

Child Dose

Oral Preoperative reduction of vascularity of the thyroid gland Child: As potassium iodide: 50-250 mg (approx 1-5 drops of a solution containing 1 g/ml) tid for 10-14 days before surgery. As strong iodine solution: 0.1-0.3 ml (or approx 3-5 drops) tid. Radiation protection against radioactive iodine Child: As potassium iodide: Infants from birth to 1 mth with a predicted thyroid exposure of >5 centigrays (cGy): 16 mg. >1 mth to 3 yr with a predicted thyroid exposure of >5 cGy: 32 mg. >3 yr to 18 yr (except adolescents approaching adult size) with a predicted thyroid exposure of >5 cGy: 65 mg. Do not exceed once-daily doses. Iodine deficiency disorders Child: As iodised oil: Infants up to 1 yr: Single dose of 100 mg iodine; 1-5 yr: 200 mg iodine; >6 yr: 400 mg iodine. Intramuscular Iodine deficiency disorders Child: As iodised oil: 380 mg iodine, as single IM doses to provide adequate protection from iodine deficiency for up to 3 yr. Infants up to 1 yr: 190 mg iodine, as iodised oil (480 mg/ml iodine).

Renal Dose

Administration

Contra Indications

Hypersensitivity. Acute bronchitis (potassium iodide).

Precautions

Pregnancy, lactation. Hyperkalaemia, hyperthyroidism, myotonia congenita, renal function impairment, tuberculosis, hypocomplementemic vasculitis, goiter, autoimmune thyroid disease. Child. Repeated admin not recommended in neonatesdue to risk of hypothyroidism.

Pregnancy-Lactation

Pregnancy Category: D Increased risk of thyroid suppression in the fetus and neonate leads to a specific recommendation that newborns and pregnant women be given priority with regard to evacuation, safe shelter, and safe food/milk during radiation emergency in order to obviate, as possible, the need for repeat dosing with KI Lactation: Excreted in breast milk

Interactions

Concurrent use with antithyroid agents may lead additional hypothyroid effect. Concurrent use with potassium-containing drugs or potassium-sparing diuretics may lead to hyperkalaemia. Potentially Fatal: Concurrent use with lithium salts may lead to additive hypothyroid effect.

Adverse Effects

Side effects of Iodine (Potassium Iodide) : Hypersensitivity reactions (urticaria, angioedema, cutaneous haemorrhage, purpura, fever, arthralgia, lymphadenopathy, eosinophilia); goitre, hypothyroidism and hyperthyroidism. Iodism on prolonged use (metallic taste, increased salivation, swelling and inflammation of throat, swollen and irritated eyes, pulmonary oedema, nausea, vomiting, diarrhoea). Potentially Fatal: Fatal periarteritis, ioderma.

Mechanism of Action

Potassium iodide participates in a complex series of reactions in the thyroid gland to produce thyroid hormones. When used for hyperthyroidism, it rapidly inhibits the release of thyroid hormones via a direct effect on the thyroid gland and inhibits the synthesis of thyroid hormones. Vascularity of the thyroid gland is reduced. When used in radiation emergencies, oral potassium iodide is admin before or promptly after intake of radioactive iodine, blocks thyroidal uptake of radioactive isotopes of iodine, thereby minimizing the risk of radiation-induced thyroid neoplasms.