Thyroxil Special Precautions

Laboratory monitoring: Levothyroxine sodium has a narrow therapeutic index.
Appropriate Levothyroxine sodium dosage is based upon clinical assessment and laboratory monitoring of thyroid function tests. During the initial titration period, careful dosage titration and monitoring is necessary to avoid the consequences of under- or over-treatment. The symptoms of excessive Levothyroxine sodium dosage are the same as many features of endogenous thyrotoxicosis. Treatment with Levothyroxine sodium in patients with pan hypopituitarism or other causes predisposing to adrenal insufficiency may cause reactions, including dizziness, weakness, malaise, weight loss, hypotension and adrenal crisis. It is advisable to initiate corticosteroid therapy before giving Levothyroxine sodium in these cases. Special patient populations: The initial dose and any dose increments should be carefully chosen in the elderly and in patients with cardiac symptoms, diabetes mellitus or insipidus: too high initial dose or too rapid increase may cause or aggravate symptoms of angina, arrhythmias, myocardial infarction, cardiac failure or a sudden raise in blood pressure.
Levothyroxine sodium should not be used for the treatment of obesity or weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for anorectic effects. Patients with myxedema have an increased sensitivity for thyroid hormones; in these patients the starting should be low with slow dosing increments. Thyroxine absorption is decreased in patients with malabsorption syndromes. It is advised to treat the malabsorption condition to ensure effective thyroxine treatment with regular thyroxine dose. During pregnancy, serum thyroxine levels may decrease with a concomitantly increase in serum TSH level to values outside the normal range. Patients taking levothyroxine should have their TSH measured during each trimester. An elevated serum TSH level should be corrected by an increase in the dose of levothyroxine. Since postpartum TSH serum levels are similar to preconception values, levothyroxine dosage can be reduced to the pre-pregnancy dose. In women, long-term levothyroxine sodium therapy has been associated with increased bone resorption, thereby decreasing bone mineral density, especially in post-menopausal women on greater than replacement doses of in women who are receiving suppressive doses of levothyroxine. To minimize the risk of osteoporosis, dosage of levothyroxine sodium should be titrated to the lowest possible level.
Pre-clinical Safety Data: No additional data of relevance.
Effects on Ability to Drive and Use Machines: From the pharmacokinetic and pharmacodynamic properties of thyroxine, treatment with Levothyroxine sodium would not be expected to interfere with ability to drive or operate machinery.