IODINE

Though iodine is a constituent of thyroid hormone it is the fastest acting thyroid inhibitor. It is reduced in the intestines to iodide and the response to iodine or iodides is identical. The gland if enlarged shrinks, becomes firm and less vascular. The thyroid status starts returning to nrmal at a rate commensurate with complete stoppage of hormone release from the gland. The gland itself involutes and colloid is restored. With daily administration, peak effects are seen in 10-15 days, after which ‘thyroid escape’ occurs and thyrotoxicosis may return with greater vengence. Important action is inhibition of hormone release-‘thyroid constipation.’

Indications

Preoperative preparation for thyroid- ectomy, prophylaxis of endemic goiter. Hypo- thyroidism, hyperthyroidism.

Contra-Indications

Pregnancy, lactation.

Special Precautions

Long term use of high doses can cause hypothyroidism and goiter. May causeflaring of acne in adolescents.

Side Effects

Swelling in lips, eye lids, angioderma of larynx, fever, joint pain, petechial haemorrhages, thrombocytopenia, lymphadenopathy. Inflammation of mucous membranes, salivation, sneezing.

Drug Interactions

Enhance hypothyroid effect with lithium. Alkalies and proteins reduce disinfectant property.