Teriparatide

Teriparatide

File:Teriparatide.png
Clinical data
Pregnancy category	C
Routes of administration	SubQ
Pharmacokinetic data
Bioavailability	95%
Metabolism	Hepatic (nonspecific proteolysis)
Biological half-life	SubQ: 1 hour
Excretion	Renal (metabolites)
Identifiers
CAS Number	52232-67-4
ATC code	H05AA02 (WHO)
PubChem	CID 16133850
Chemical data
Formula	C181H291N55O51S2
Molar mass	4117.72 g/mol[[]]

Teriparatide (Forteo) is a recombinant form of parathyroid hormone, used in the treatment of some forms of osteoporosis. It is manufactured and marketed by Eli Lilly and Company.

Administration

Teriparatide is administered by injection once a day in the thigh or abdomen. The recommended dose is 20 μg per day.

Uses

Teriparatide has an ongoing clinical trial to evaluate its effectiveness in treating the symptoms of osteogenesis imperfecta.

Teriparatide should not be prescribed for patients who are at increased risks for osteosarcoma. This includes those with Paget's Disease of bone or unexplained elevations of serum alkaline phosphate, open epiphysis, or prior radiation therapy involving the skeleton.

Side Effects

The main risk of teriparatide is an increased risk of osteosarcoma, at least as seen in rat studies. Because of this risk, it is typically used as second line therapy and even then for no more than two years.

Mechanism of action

Teriparatide is the portion of human parathyroid hormone (PTH), amino acid sequence 1 through 34, of the complete molecule (containing 84 amino acids). Endogenous PTH is the primary regulator of calcium and phosphate metabolism in bone and kidney. PTH increases serum calcium, partially accomplishing this by increasing bone resorption. Thus, chronically elevated PTH will deplete bone stores. However, intermittent exposure to PTH will activate osteoblasts more than osteoclasts. Thus, once-daily injections of teriparatide have a net effect of stimulating new bone formation leading to increased bone mineral density.

Teriparatide is the first, and to date only, FDA approved agent for the treatment of osteoporosis that stimulates new bone formation.

FDA approval

Teriparatide was approved by the Food and Drug Administration (FDA) on 26 November 2002, for the treatment of osteoporosis in men and postmenopausal women who are at high risk for having a fracture. The drug is also approved to increase bone mass in men with primary or hypogonadal osteoporosis who are at high risk for fracture.

References

One randomized trial of postmenopausal women who had already fractured vertebra compared teriparatide at either 20 or 40 micrograms per day with placebo. After about 19 months, 14% of the women taking placebo had new vertebral fractures, as compared with 5% of the women taking 20 micrograms of teriparatide and 4% of the women taking 40 micrograms. There were also a statistically significant lower number of non-vertebral fractures in the teriparatide treated group. 20 micrograms of teriparatide increased spine and hip bone mineral density. no

N Engl J Med. 2001 May 10;344(19):1434-41.

External links

• Teriparatide at National Institutes of Health.
• When to Use Teriparatide - Medscape.

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