Levothyroxine Sodium Tablets Dosage & Rx Info

Levothyroxine Sodium Tablets Generic Name & Formulations

Legal Class

General Description

Levothyroxine sodium 25mcg, 50mcg, 75mcg, 88mcg, 100mcg, 112mcg, 125mcg, 137mcg, 150mcg, 175mcg, 200mcg, 300mcg.

Pharmacological Class

T₄ (synthetic).

How Supplied

Contact supplier

Manufacturer

Various generic manufacturers

Mechanism of Action

The mechanisms by which thyroid hormones exert their physiologic actions are not completely understood, but it is thought that their principal effects are exerted through control of DNA transcription and protein synthesis. T₃ and T₄ diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins. The physiological actions of thyroid hormones are produced predominantly by T₃, the majority of which (approximately 80%) is derived from T₄ by deiodination in peripheral tissues.

Levothyroxine Sodium Tablets Indications

Indications

Hypothyroidism.

Levothyroxine Sodium Tablets Dosage and Administration

Adult

Maintenance: 100–200mcg daily. Complications: titrate dose.

Children

<6months: 8–10mcg/kg per day. 6months–1yr: 6–8mcg/kg per day. 1–5yrs: 5–6mcg/kg per day. 6–12yrs: 4–5mcg/kg per day.

Levothyroxine Sodium Tablets Contraindications

Contraindications

Thyrotoxicosis. Acute MI. Uncorrected adrenal insufficiency.

Levothyroxine Sodium Tablets Boxed Warnings

Not Applicable

Levothyroxine Sodium Tablets Warnings/Precautions

Warnings/Precautions

Not for treatment of obesity. Cardiovascular disease. Diabetes. Adrenal insufficiency. Increased sensitivity in myxedema, severe hypothyroidism. Pregnancy. Nursing mothers.

Levothyroxine Sodium Tablets Pharmacokinetics

Distribution

Plasma protein bound: >99%.

Metabolism

Hepatic.

Elimination

Renal. Half-life: 6–7 days (T₄), 1–2 days (T₃).

Levothyroxine Sodium Tablets Interactions

Interactions

Potentiates sympathomimetics. Monitor antihyperglycemics, oral anticoagulants.

Levothyroxine Sodium Tablets Adverse Reactions

Adverse Reactions

Hyperthyroidism; transient hair loss in children.

Levothyroxine Sodium Tablets Clinical Trials

See Literature

Levothyroxine Sodium Tablets Note

Notes

Formerly known under the brand name Levothroid.

Levothyroxine Sodium Tablets Patient Counseling