Teriparatide dosing

Teriparatide can be used if bisphosphonates are not tolerated or contraindicated. Testosterone replacement therapy should be considered in men, and high-dose hormonal oral contraceptives can be considered for premenopausal women with documented hypogonadism. 

Teriparatide (Forteo) [Antiosteoporotic/Parathyroid Hormono] WARNING T Osteosarcoma risk in animals, therefore only use in pts for whom the potential benefits outweigh risks Uses Severe/refractory osteoporosis Action PTH (recombinant) Dose 20 meg SQ daily in thigh or abd Caution [C, /-] Contra w/ Paget Dz, prior radiation, bone metastases, T Ca caution in urolithiasis Disp Inj SE Orthostatic X BP on administration, N/D, T... 

Despite early promise that fluoride might be useful in the prevention or treatment of postmenopausal osteoporosis, this form of therapy remains controversial. A new formulation of fluoride (slow release, lower dose) appears to avoid much of the toxicity of earlier formulations and may reduce fracture rates. This formulation is under consideration for approval by the FDA. Teriparatide, the recombinant form of PTH 1-34, has recently been approved for treatment of osteoporosis. Teriparatide is given in a dosage 20 Mg subcutaneously daily. Like fluoride, teriparatide stimulates new bone formation, but unlike fluoride this new bone appears structurally normal and is associated with a substantial reduction in the incidence of fractures. 

Two carcinogenicity bioassays were conducted in rats (3-60x MRHD). Treatment resulted in a marked dose-related increase in the incidence of osteosarcoma, a rare mahgnant bone tumor, in both male and female rats. Osteosarcomas were observed at all doses and the incidence reached 40-50% in the high-dose groups. Teriparatide also caused a dose-related increase in osteoblastoma and osteoma in both sexes. Bone tumors in rats occurred in association with a large increase in bone mass and focal osteoblast hyperplasia Second 2-year study was carried out in order to determine the effect of treatment duration and animal age on the development of bone tumors. Female rats were treated for different periods between 2 and 26 months of age (at 3x to 20x MRHD based on body surface area). The... 

In male and female rats, teriparatide caused an increase in the incidence of osteosarcoma (a mahgnant bone tumor) that was dependent on dose and treatment duration. Effect was observed at systemic exposures to teriparatide ranging from 3 to 60 times the exposure in humans given a 20 meg dose. 

Vahle JL, Long GG, Sandusky G, Westmore MS, Ma YL, Sato M. Bone neoplasms in F344 rats given teriparatide [rhPTH(l-34)] are dependent on duration of treatment and dose. Toxicol Pathol 2004 32(4) 426-38. 

Each prefilled delivery device is filled with 3.3 mL to deliver 3 mL. Each milliliter contains 250 meg of teriparatide (corrected for acetate, chloride, and water content), 0.41 mg of glacial acetic acid, 0.10 mg of sodium acetate (anhydrous), 45.4 mg of mannitol, 3.0 mg of m-cresol, and water for injection. In addition, hydrochloric acid solution 10% and/or sodium hydroxide solution 10% may have been added to adjust the product to pH 4. Each cartridge preassembled into a pen device delivers 20 meg of teriparatide per dose each day for up to 28 days. 

Teriparatide contains the first 34 amino acids in human parathyroid hormone and represents a novel approach to osteoporosis treatment. Although hyperparathyroidism leads to bone loss (see Fig. 88-3), therapeutic doses (for shorter periods of time) conversely improve BMD and rednce fractnre risk. Parathyroid hormone is currently the only approved osteoporosis medication that works by stimulating bone formation. Becanse of adverse effects and cost concerns, teriparatide is reserved for treating those at high risk of osteoporosis-related fracture who cannot or will not take or have failed bisphosphonate therapy. 

Teriparatide is commercially available as a prefiUed 3-mL pen-type delivery device that administers subcutaneous injections in the thigh or abdominal area (see Table 88-6). The initial dose should be administered with the patient either sitting or lying down in case orthostatic hypotension occurs. Health care providers should re-educate patients about syringe use with each refill, and the patient or caregiver should also re-read the user s manual each month. The pen should be refrigerated and can be used for up to 28 days following the initial injection. Teriparatide is also the most expensive of the approved osteoporosis therapies. 

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