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Related to Synthroid: Levothyroxine, hypothyroidism, Eltroxin


trademark for a preparation of levothyroxine sodium, a thyroid hormone.

levothyroxine sodium (L-thyroxine, T4)

Eltroxin (CA) (UK), Euthyrox (CA), Evotrox (UK), Levo-T, Levolet, Levothroid, Levoxyl, Nu-Thyro (CA), Soloxine, Synthroid, Unithroid

Pharmacologic class: Synthetic thyroxine hormone

Therapeutic class: Thyroid hormone replacement

Pregnancy risk category A

FDA Box Warning

• Drug shouldn't be used alone or with other agents to treat obesity or weight loss. In euthyroid patients, doses within range of daily hormonal requirements are ineffective for weight loss. Larger doses may cause serious or life-threatening toxicity, particularly when given with sympathomimetic amines (such as those used for anorectic effects).


Synthetic form of thyroxine that replaces endogenous thyroxine, increasing thyroid hormone levels. Thyroid hormones help regulate cell growth and differentiation and increase metabolism of lipids, protein, and carbohydrates.


Powder for injection: 200 mcg/vial in 6- and 10-ml vials, 500 mcg/vial in 6- and 10-ml vials

Tablets: 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg, 300 mcg

Indications and dosages

Hypothyroidism; treatment or prevention of euthyroid goiter

Adults: For healthy adults younger than age 50 and those over age 50 who have recently been treated or undergone short-term therapy, start at full replacement dosage of 1.7 mcg/kg P.O. daily, given 30 minutes to 1 hour before breakfast. For patients older than age 50 or younger than age 50 with heart disease, 25 to 50 mcg P.O. daily, increased q 4 to 6 weeks. In severe hypothyroidism, initial dosage is 12.5 to 25 mcg P.O. daily, adjusted by 25 mcg daily q 2 to 4 weeks. For patients who can't tolerate oral doses, adjust I.M. or I.V. dosage to roughly half of oral dosage.

Congenital hypothyroidism

Children older than age 12 who have completed puberty and growth: 1.7 mcg/kg P.O. daily

Children older than age 12 who have not completed puberty and growth: Up to 150 mcg or 2 to 3 mcg/kg P.O. daily

Children ages 6 to 12: 4 to 5 mcg/kg P.O. daily

Children ages 1 to 5: 5 to 6 mcg/kg P.O. daily

Infants ages 6 to 12 months: 6 to 8 mcg/kg P.O. daily


A trademark for the drug levothyroxine sodium.


a trademark for a thyroid hormone (levothyroxine sodium).
References in periodicals archive ?
Do not use SYNTHROID if you have hyperthyroidism or over-active thyroid, uncorrected adrenal problems, are having symptoms of a heart attack, or are allergic to any of its ingredients.
To facilitate my mother's receiving Synthroid, we would have needed to get the information from her primary care doctor, who issued the prescription.
Your body is able to turn the prescription drug Synthroid into the [T.
He was surprised to find that his magnesium supplement reacted with his thyroid medication, preventing Synthroid from being absorbed.
At the same time, lucrative Abbott drugs Biaxin for infection and Synthroid for thyroid disorders face competition from cheaper, generic drugs, and a potential prostate cancer drug, Xinlay, ran into a delay before regulators who wanted more data.
in 2005, thyroid medications Synthroid and Levoxyl ranked 4th and 24th, respectively, among all brand-name prescriptions filled nationally.
Her prescription medications included Wellbutrin, Xanax, Synthroid, and Prilosec, and her OTC medications included Tylenol and Motrin for her migraines.
A recently approved generic formulation of levothyroxine "is significantly more potent" than Synthroid, and could lead to serious side effects if a patient were switched from one to the other, two clinical endocrinology organizations have warned.
CALCIUM AND MEDICATIONS If you're taking a bisphosphonate medication for osteoporosis (Fosamax, Didrocal) or Synthroid for hypothyroidism, take your calcium pills at separate times of the day since the mineral can interfere with the absorption of these drugs.
At the time, Synthroid was the market leader and the most expensive drug in its class.
Integrative medical practitioners will give hypothyroid women thyroid supplements, but usually get better results using a T4 and T3 thyroid replacement rather than the T4-only products such as Synthroid.
For example, Boots Pharmaceuticals, sole manufacturer of Synthroid ($600 billion market), enlisted the University of California-San Francisco (UCSF) to prove that no other competing preparations of Synthroid were bioequivalent.