Levothyroxine

Sodium Levothyroxine. As one of the active principles of the thyroid gland, sodium levothyroxine [55-03-8] (levothyroxine sodium) can be obtained either from the thyroid glands of domesticated animals (10) or synthetically. It should contain 61.6—65.5% iodine, corresponding to 100 3% of the pure salt calculated on an anhydrous basis. Its chiral purity must also be ascertained because partial racemi2ation may occur during synthesis and because dl-T is available commercially. Sodium levothyroxine melts with decomposition at ca 235°C. It is prepared as pentahydrate [6106-07-6] from... 

Levatrom - Clofibrate Levaxin - Levothyroxine sodium Levjcor -Metaraminol Levisul Sulfadimethoxine Levium Diazepam Levius Aspirin... 

The absorption of oral iron is decreased when tlie agent is administered with antacids, tetracyclines, penicillamine, and the fluoroquinolones. When iron is administered with levothyroxine, there may be a decrease in tlie effectiveness of levothyroxine When administered orally, iron deceases the absoqition of lev-odopa. Ascorbic acid increases tlie absoqition of oral iron. Iron dextran administered concurrently with chloramphenicol increases serum iron levels. 

Promoting an Optimai Response to Therapy Thyroid hormones are administered once a day, early in the morning and preferably before breakfast. An empty stomach increases the absorption of the oral preparation. Levothyroxine (Synthroid) also can be given intravenously and is prepared for administration immediately before use ... 

CJ6H13I2NO5 94298-44-9) see Dextrothyroxine L-/V-formyl-3,5-diiodothyronine (CifiHi3l2NOj) see Levothyroxine D(-)-A/-formyl-3,5-diiodothyronine ( i6Hi3l2N05 120408-14-2) see Dextrothyroxine N-formyl-l,5-dimethyl-4-hexenamine (CyH,7NO) see Heptaminol 10-formylfolic acid... 

Lithium is concentrated in the thyroid gland and can impair thyroid hormone synthesis. Although goiter is uncommon, as many as 30% of patients develop at least transiently elevated thyroid-stimulating hormone values. Lithium-induced hypothyroidism is not usually an indication to discontinue the drug. Patients can be supplemented with levothyroxine if continuation of lithium is desired.30... 

Describe the clinical use of levothyroxine in the treatment of hypothyroidism, including initial dose and dose titration, and patient monitoring. 

Discuss the issues regarding levothyroxine product bioequivalence and the advantages of maintaining patients on the same product. 

Despite the availability of a wide array of thyroid hormone products, it is clear that synthetic levothyroxine (LT4) is the treatment of choice for almost all patients with hypothyroidism. LT4 mimics the normal physiology of the thyroid gland, which secretes mostly T4 as a prohormone. As needed, based on metabolic demands, peripheral tissues convert thyroxine (T4)... 

Levothyroxine (Synthroid , Levoxyl , Unithroid ), other brands, and generics Synthetic LT4 25, 50, 75, 88, 100, 112, 125, 137, 150, 1 75, 200, and 300 meg tablets 500 meg vial for injection 60 meg Gold standard for treating hypothyroidism products not therapeutically equivalent full replacement dose 1-1.6 meg/kg per day when switching from animal product, lower calculated daily dose by 25-50 meg intravenous form rarely needed... 

Common adverse effects of calcium salts include constipation, bloating, cramps, and flatulence. Changing to a different salt form may alleviate symptoms for some patients. Calcium salts may reduce the absorption of levothyroxine, iron and some antibiotics, such as tetracycline and fluoroquinolones. 

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