Teriparatide: Uses, Mechanism, and Reported Side Effects

For people living with osteoporosis and a history of fracture, finding a treatment that actively builds bone rather than just slowing its loss is a major concern. Teriparatide is one of the few approved therapies designed to do exactly that.

Key takeaways

• Teriparatide is a parathyroid hormone analog approved for several forms of osteoporosis.
• It works by mimicking the bone-building actions of natural parathyroid hormone.
• Approved uses include postmenopausal, male, and glucocorticoid-induced osteoporosis in high-risk patients.
• Nearly 200 registered trials have studied teriparatide, including completed phase 4 work.
• The most commonly reported adverse events involve musculoskeletal pain, dizziness, and falls.

What Teriparatide Is

Teriparatide belongs to a drug class known as parathyroid hormone analogs. It is built from the same 34 N-terminal amino acids found in the active portion of natural human parathyroid hormone (PTH). In the body, PTH regulates calcium and phosphate metabolism in bone and kidney, and it influences how much calcium the intestines absorb. Teriparatide binds to the same high-affinity cell-surface receptors as natural PTH, triggering similar effects on bone metabolism.

What Teriparatide Is Approved For

Teriparatide, marketed under the brand name Teriparatide, is approved for the treatment of postmenopausal women with osteoporosis who are at high risk for fracture, including those with a prior osteoporotic fracture or multiple risk factors, or who have not responded to other osteoporosis therapies. In this population, it reduces the risk of both vertebral and nonvertebral fractures. It is also approved to increase bone mass in men with primary or hypogonadal osteoporosis who are at high fracture risk or intolerant to other treatments. A third approved use covers men and women with osteoporosis caused by sustained systemic glucocorticoid therapy at daily doses equivalent to 5 mg or more of prednisone, in those at high risk. The label for teriparatide does not carry a boxed warning.

What the Evidence Shows

Teriparatide has been studied in 197 registered clinical trials. A completed phase 4 study examined its mechanism of action in postmenopausal women, while a separate phase 4 trial compared teriparatide combined with denosumab against placebo for atraumatic bone marrow edema, though that trial was suspended. Other research, including a completed study on vitamin D activation in secondary hyperparathyroidism, has explored related aspects of parathyroid hormone biology.

Reported Side Effects

Reports submitted to FAERS for teriparatide most frequently describe musculoskeletal and general symptoms, including arthralgia (8,726 reports), pain in extremity (8,377), pain (7,579), and back pain (5,949). Nausea (9,026 reports) was the single most reported term overall, and dizziness (8,337) and falls (7,935) were also common, along with fatigue (7,225). These figures represent counts of submitted reports, not confirmed incidence rates or evidence of a causal link between teriparatide and the reaction.