* One of the synthetic [T.sub.4] drugs (brand names Synthroid, Levoxyl, Levothroid
, and Unithroid; generic name levothyroxine);
It also discusses management of hypothyroidism and use of thyroid hormone replacement therapy, particularly levothyroxine (synthetic T4) (Levo-T, Levolet, Levothroid
, Levoxyl, Novothyrox, Synthroid, Unithroid, and generics) and briefly addresses hyperthyroidism resulting from overtreatment of hypothyroidism.
Abbott Laboratories and Forest Pharmaceuticals, manufacturer of Levothroid
, filed New Drug Applications in August but had not received approval at press time.
Doctors complain about thyroid test results that don't seem to agree, thyroid test results that don't support their clinical impression, and a TSH that's too high in patients taking the usual dosage of levothyroxine (Levothroid
, Levoxine, Synthroid).
Generic preparations of L-thyroxine may not be bioequivalent to brand products. Several brand-name products are available; among them, Levothroid
and Synthroid, were shown to be therapeutically interchangeable.
When dealing with hypothyroidism, for example, naturopaths often measure T3 and T4 levels in addition to ordering the thyroid stimulating hormone (TSH) test, and they recommend T3-T4 preparations, such as desiccated thyroid, instead of standardized Levothroid
Pittsburgh-based Mylan is also marketing generic Levothroid
(levothyroxine sodium), a thyroid activity treatment equivalent to Forest Laboratories Inc.'s brand product.
Food and Drug Administration (FDA): Unithroid, Levoxyl, Synthroid, Levothroid
, Levolet, Levo-T, and Novothyrox (only the first four are currently being marketed in the US).
Drug Dosage Cost/Day levothyroxine 1.6 [micro]g/kg $0.18 * (Levothroid
, (on average) (Levothroid
); Levoxyl, $0.21* Synthroid, (Levoxyl); Unithroid) $0.36 * Synthroid, $0.37 ** (Unithiroid) (for a 70-kg patient) liothyronine 25 [micro]g b.i.d.
Drug Dosage Cost/Day levothyroxine 1.6 [micro]/kg (on $0.18 * (Levothroid
, average) (Levothroid
); Levoxyl, $0.21 * Synthroid, (Levoxyl); Unithroid) $0.36 * (Synthroid); $0.37 ** (Unithroid) (for a 70-kg patient) liothyronine 25 [micro] b.i.d.
There are three branded oral T4 products available in the United States: levothyroxine sodium (Levoxyl, Synthroid and Levothroid
(1) In addition to manufacturing Armour Thyroid, Forest makes Levothroid
, a proprietary brand of levothyroxine (synthetic thyroxine, or T4).