The following information is obtained from various newswires,
published medical journal articles, and medical conference presentations.
Company: Genpharm
Approval Status: Approved May 2002
Treatment for: Hypothyroidism and suppression of thyroid-stimulating hormone
General Information
Novothyrox (levothyroxine sodium) is a thyroid hormone replacement drug to treat Hypothyroidism and suppression of thyroid-stimulating hormone. Novothyrox is a tablet administered as a once-daily therapy. The dose necessary to achieve normal thyroid hormone levels is dependent on several factors, including, but not limited to the patient's age, weight, and cardiovascular status, as well as the nature of the condition being treated. The average full replacement dose of levothyroxine is approximately 1.7 mcg/kg/day.
Side Effects
Adverse reactions associated with levothyroxine therapy are usually symptoms of hyperthyroidism due to therapeutic overdosage.
Mechanism of Action
Synthetic levothyroxine (T4) is identical to that produced naturally in the human thyroid gland.
Thyroid hormone synthesis and secretion is regulated by the hypothalamic-pituitarythyroid
axis. Thyrotropin-releasing hormone (TRH) released from the hypothalamus
stimulates secretion of thyrotropin-stimulating hormone, TSH, from the anterior
pituitary. TSH, in turn, is the physiologic stimulus for the synthesis and secretion of
thyroid hormones, L-thyroxine (T4) and L-triiodothyronine (T3), by the thyroid gland. Circulating serum T3 and T4 levels exert a feedback effect on both TRH and TSH secretion. When serum T3 and T4 levels increase, TRH and TSH secretion decrease. When thyroid hormone levels decrease, TRH and TSH secretion increase. (From Novothyrox prescription label)
Additional Information
In July 2001, the FDA announced that it would require all manufacturers of levothyroxine sodium products to submit New Drug Applications for approval of these products. This guidline applies to both original and generic forms of the levothyroxine sodium drugs.
For more information about this FDA ruling, please refer to the guidance itself on the FDA web site at www.fda.gov/cder/guidance/4647fnl.htm.
