Endogenous 84-amino acid parathyroid hormone (PTH) is the primary regulator of calcium and phosphate metabolism in bone and kidney. Physiological actions of PTH include regulation of bone metabolism, renal tubular reabsorption of calcium and phosphate, and intestinal calcium absorption. The biological actions of PTH and teriparatide are mediated through binding to specific high-affinity cell-surface receptors. Teriparatide and the 34 N-terminal amino acids of PTH bind to these receptors with the same affinity and have the same physiological actions on bone and kidney. Teriparatide is not expected to accumulate in bone or other tissues. The skeletal effects of teriparatide depend upon the pattern of systemic exposure. Once-daily administration of teriparatide stimulates new bone formation on trabecular and cortical (periosteal and/or endosteal) bone surfaces by preferential stimulation of osteoblastic activity over osteoclastic activity. In monkey studies, teriparatide improved trabecular microarchitecture and increased bone mass and strength by stimulating new bone formation in both cancellous and cortical bone. In humans, the anabolic effects of teriparatide manifest as an increase in skeletal mass, an increase in markers of bone formation and resorption, and an increase in bone strength. By contrast, continuous excess of endogenous PTH, as occurs in hyperparathyroidism, may be detrimental to the skeleton because bone resorption may be stimulated more than bone formation.

Teriparatide is a parathyroid hormone analog, (PTH 1-34), indicated for:

• Treatment of postmenopausal women with osteoporosis at high risk for fracture.
• Increase of bone mass in men with primary or hypogonadal osteoporosis at high risk for fracture.
• Treatment of men and women with osteoporosis associated with sustained systemic glucocorticoid therapy at high risk for fracture.

• Treatment of Postmenopausal Women with Osteoporosis at High Risk for Fracture: The recommended dose is 20 mcg subcutaneously once a day.
• Increase of Bone Mass in Men with Primary or Hypogonadal Osteoporosis at High Risk for Fracture: The recommended dose is 20 mcg subcutaneously once a day.
• Treatment of Men and Women with Glucocorticoid-Induced Osteoporosis at High Risk for Fracture: The recommended dose is 20 mcg subcutaneously once a day.

Administration

• Teriparatide should be administered as a subcutaneous injection into the thigh or abdominal wall. There are no data available on the safety or efficacy of intravenous or intramuscular injection of Teriparatide.
• Teriparatide should be administered initially under circumstances in which the patient can sit or lie down if symptoms of orthostatic hypotension occur
• Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Teriparatide is a clear and colorless liquid. Do not use if solid particles appear or if the solution is cloudy or colored.
• Patients and caregivers who administer Teriparatide should receive appropriate training and instruction on the proper use of the Teriparatide delivery device from a qualified health professional

Do not use Teriparatide in patients with hypersensitivity to teriparatide or to any of its excipients. Reactions have included angioedema and anaphylaxis.

Most common adverse reactions include: arthralgia, pain, and nausea.

• Patients with Paget’s disease of bone, pediatric and young adult patients with open epiphyses, and patients with prior external beam or implant radiation involving the skeleton: Should not be treated with Teriparatide
• Treatment duration: Use of Teriparatide for more than 2 years during a patient’s lifetime is not recommended.
• Patients with bone metastases, history of skeletal malignancies, metabolic bone diseases other than osteoporosis, or hypercalcemic disorders: Should not be treated with Teriparatide
• Laboratory alterations: Teriparatide may increase serum calcium, urinary calcium, and serum uric acid
• Urolithiasis: Use with caution in patients with active or recent urolithiasis because of risk of exacerbation
• Orthostatic hypotension: Transient orthostatic hypotension may occur with initial doses of Teriparatide.

Use in Special Populations

Pediatric Use: The safety and efficacy of Teriparatide have not been established in any pediatric population.

• Hepatic Impairment: No studies have been performed in patients with hepatic impairment.

Pregnancy & Lactation

There are no available data on Teriparatide use in pregnant women to evaluate for drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Consider discontinuing Teriparatide when pregnancy is recognized. It is not known whether teriparatide is excreted in human milk, affects human milk production, or has effects on the breastfed infant.