THYROXINE SODIUM
Due to failure of thyroid development extreme iodine deficiency or a defect in hormone synthesis symptoms of cretinism are detected during infancy or childhood. Treatment with thyroxine will restore physical growth & development and further mental retardation is prevented. Due to deficient production of thyroid hormone leads to excess TSH leading to thyroid enlargement, more efficient trapping of iodide occurs & probably greater proportion of T3 is synthesized resulting in enough hormone production to meet peripheral demands. Thus treatment with thyroxine is replacement therapy in this condition also, despite no overt hypothyroidism.Cretinism, adult hypothyroidism, myxoedema coma, nontoxic goiter. Papillary carcinoma of thyroid.
Initially 50-100 mcg daily, before breakfast, and adusted at 3-4 wks intervals by 50 mcg until normal metabolism is steadily maintained, this may require doses of 150-300 mcg daily over 50 yrs. : Max.: 50 mcg daily.Cardiac disease.Max.:25 mcg daily or 50 mcg on alternate days.For cretinous infants:Initially 25mcg daily increasing by 25mcg every 2-4 wks. Juvenile myxoedema : 2.5-5mcg/kg/day.
Thyrotoxicosis,hypersensitivity.
Patients with panhypo-pituitarism or other causes predisposing to adrenal insufficiency may react unfavourably to thyroxine treatment, & it is advisable to initiate corticosteroid therapy before giving thyroxine in these cases. Special care is needed when there are symptoms of myocardial insufficiency or ECG evidence of myocardial infarction.
Anginal pain, cardiac arrhythmias, palpitation, and cramps in skeletal muscle, tachycardia, diarrhoea, restlessness, excitabilit, headache, flushing, sweating, excessive loss of weight and muscular weakness.
Enhances effect of oral anticoagulants. Aspirin and phenytoin enhance effect of thyroxine. Cholestyramine reduces absorption. Amiodarone elevates thyroxine levels.
