TFour

Levothyroxine Na

Thyroid hormone replacement. Under active thyroid (hypothyroidism) & other types of thyroid disorders (eg, certain types of goiters, thyroid nodules, thyroiditis, & thyroid cancer).

Adult Initially 50-100 mcg increased by 25-50 mcg at 3-4 wk intervals to maintain max 150-300 mcg daily. Childn Initially 25-150 mcg w/ 25 mcg increments every 2-4 wk. >1 yr Juvenile myxedema 2.5-5 mcg/kg/day.

Should be taken on an empty stomach: Take 30 min to 1 hr before meals.

Hypersensitivity. Thyrotoxicosis.

CHD, ECG changes of MI. Corticosteroid therapy should be given 1st followed by thyroxine in patients w/ adrenal insufficiency. Should not be used alone or in combination w/ diet pills to treat obesity or for wt loss. Pregnancy & lactation.

Palpitation, osteoporosis, angina, tremors, thyrotoxicosis, allergic reaction, headache, tachycardia, diarrhea, restlessness, sweating, wt loss & muscle weakness.

Increases effect of anticoagulants & may cause excessive hypoprothrombinemia & bleeding. May increase levels of phenytoin. Enhanced metabolism of thyroid hormones & possible displacement from plasma proteins w/ carbamazepine & phenytoin. Cardiac glycosides. Enhanced effects of sympathomimetic agents. Increased receptor sensitivity to catecholamines thus accelerating response to TCAs. Reduced GI absorption w/ cholestyramine. Decreased absorption w/ bile acid sequestrants (eg, colestipol), anion/cation exchange resins (eg, kayexalate, sevelamer), sucralfate, Ca carbonate, & ferrous sulfate. Increased serum conc of thyroxine-binding globulin w/ OC, estrogen, tamoxifen, clofibrate, methadone, & 5-fluorouracil. May increase thyroid hormone requirements w/ HMG-CoA reductase inhibitors (statins). Decreased serum conc of thyroxine-binding globulin w/ androgens & anabolic steroids. Increased levothyroxine Na dosage requirements in hypothyroid patients when used w/ tyrosine kinase inhibitors (eg, imatinib & sunitinib), & amiodarone. Large doses w/ diet pills may cause symptoms of toxicity.

Thyroid Hormones

H03AA01 - levothyroxine sodium ; Belongs to the class of thyroid hormones.

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