Abaloparatide
Parathyroid hormone (PTH) analogues
Parathyroid hormone (PTH) analoguesPregnancy: contraindicated
It is not used in pregnancy or breastfeeding.
A daily injection of a PTH-related peptide analogue that builds new bone. Used in osteoporosis at high fracture risk.
Quick facts
- Group
- Parathyroid hormone (PTH) analogues
- Target
- Parathyroid hormone/PTHrP receptor type 1 (PTH1R)
- Used for
- Osteoporosis at high fracture risk
- Key effects
- Dizziness · Nausea · Redness
- Monitor
- Serum calcium and · Bone mineral density
- ATC
- H05AA04
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows abaloparatide itself bound to the human PTH1R receptor with its Gs protein (cryo-EM).
Abaloparatide is a synthetic analogue of the first 34 amino acids of PTH-related peptide (PTHrP). Given once a day, it briefly activates the PTH1 receptor on osteoblasts and their precursors, a Gs-coupled receptor that raises cAMP. These short pulses favour bone formation over resorption, so new bone is laid down and fracture risk falls. It raises serum calcium less than teriparatide.
- Abaloparatide activates PTH1R on osteoblast-lineage cells
- Brief daily cAMP pulses favour bone formation
- New bone is added to trabecular and cortical surfaces
- Bone density rises and fractures decrease
Indications
- Osteoporosis at high fracture risk in postmenopausal women (and in men in some approvals) Osteoporosis →
Adverse effects
Common
- Dizziness, fast or pounding heartbeat and light-headedness on standing, usually within hours of a dose
- Nausea, upper abdominal pain, headache and tiredness
- Redness, pain or swelling at the injection site
- Higher urine calcium and serum uric acid
Contraindications
- Higher baseline risk of osteosarcoma: Paget's disease of bone, unexplained high alkaline phosphatase, open growth plates, previous skeletal radiotherapy, bone metastases or bone cancer
- Hypercalcaemia or hyperparathyroidism
- Pregnancy and breastfeeding
Key interactions
- Calcium and vitamin D supplements
- Often recommended alongside; reviewed if serum calcium rises
- Bisphosphonates or denosumab
- Started after the course to keep the bone gained
What is monitored
- Serum calcium and, in people with stones, urine calcium
- Blood pressure and pulse when starting
- Bone mineral density
Administration and safety
- Subcutaneous injection into the lower abdomen, avoiding the area around the navel, with daily site rotation
- The first doses are given where the person can sit or lie down at once
- The pen is discarded 30 days after first use; the solution should be clear and colourless
- Total treatment time is limited
Pregnancy and breastfeeding
It is not used in pregnancy or breastfeeding.
Nursing care
- Teach injection technique and site rotation
- Warn about dizziness or fainting after injection and advise sitting or lying down
- Teach the signs of high calcium: nausea, constipation, weakness, low energy
- Ask about back or flank pain or blood in the urine (stones)
Pharmacokinetics
- Absorption
- Given by subcutaneous injection into the lower abdomen once a day
Test yourself
Think of the answer, then tap the question to see it.
Which natural peptide is abaloparatide modelled on?
Parathyroid hormone-related peptide (PTHrP), its first 34 amino acids; it acts on the PTH1 receptor.
Why does daily abaloparatide build bone while continuous PTH excess destroys it?
Brief daily pulses of PTH1R activation favour osteoblast bone formation over resorption.
Which early adverse effect means the first doses are given while seated or lying?
Orthostatic hypotension: dizziness, palpitations or fainting soon after the injection.
Connections
← Back to the class: Parathyroid hormone (PTH) analogues
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Abaloparatide Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.