Bone & endocrine
Teriparatide
The active fragment of human parathyroid hormone, used as the main bone-building treatment for severe osteoporosis. Strong evidence, and a good example of dose timing changing a drug's entire effect.
What it is
Teriparatide is recombinant human parathyroid hormone fragment 1–34 — the first 34 amino acids of the body's own PTH. Given once daily it builds bone rather than breaking it down. It is an approved prescription medicine (Forteo / Forsteo) for osteoporosis at high fracture risk, used for up to 24 months.
How it works
- 1
Intermittent daily exposure to PTH stimulates osteoblasts, the cells that build bone, more than it stimulates osteoclasts, the cells that break it down.
- 2
The result is new bone formation on trabecular and cortical surfaces, with gains in bone mineral density and improvements in bone architecture.
- 3
Continuous PTH exposure has the opposite net effect — bone resorption. Dose timing, not just the molecule, determines the result.
- 4
This 'anabolic window' is why teriparatide is given as a short daily course, usually followed by an antiresorptive drug to lock in the gains.
What it's studied for
Reported and studied effects
- About 65% reduction in vertebral fractures and 53% reduction in non-vertebral fractures over a median 19 months in the pivotal trial
- Spinal bone mineral density increases of roughly 9–13%
- Rapid early rise in bone-formation markers
- Modest, transient increases in serum calcium
Research protocol notes
Research context onlyResearch context only — this is a prescription medicine. The pivotal trial used 20 micrograms subcutaneously once daily for a median of 19 months; regulators limit total treatment to 24 months. Calcium and vitamin D are usually co-prescribed and bone density is monitored.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- Nausea and dizziness
- Leg cramps
- Transient hypercalcaemia
- Brief drop in blood pressure after the first doses (orthostatic hypotension)
- Injection-site reactions
- Osteosarcoma observed in rats — a boxed warning; human risk after short courses is not established
Contraindications and cautions
- Previous skeletal malignancy or prior skeletal radiotherapy
- Paget's disease of bone
- Unexplained elevation of alkaline phosphatase
- Preexisting hypercalcaemia
- Pregnancy and breastfeeding
- Children and young adults with open growth plates
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
A large randomised controlled trial with fracture endpoints, consistent replication across populations, mechanistic clarity and decades of regulatory-approved clinical use.
References
- 01Neer et al., Effect of Parathyroid Hormone (1-34) on Fractures and Bone Mineral Density in Postmenopausal Women with Osteoporosis, NEJM 2001
- 02European Medicines Agency — Forsteo product information
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
Related
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