Pharmacological treatments for osteoporosis fall into two broad categories. Understanding the distinction is important when discussing treatment options with your consultant:
- Antiresorptive Agents: Slow or prevent further bone loss by inhibiting osteoclast activity — the cells that break down bone. They stabilise bone density and reduce fracture risk but do not directly build new bone. (Examples: bisphosphonates, denosumab, raloxifene, HRT)
- Anabolic Agents: Stimulate new bone formation by activating osteoblast activity — the cells that build bone. They can achieve meaningful bone density gains and are particularly appropriate for patients with very low bone density or high fracture risk. (Examples: teriparatide, romosozumab, abaloparatide)
Antiresorptive Group
Bisphosphonates
UK brand: Alendronic acid (Binosto, Fosamax); Risedronate (Actonel); Ibandronate (Bonviva); Zoledronic acid (Aclasta)
Mechanism: Inhibit osteoclast-mediated bone resorption, reducing both cortical and trabecular bone loss. First-line pharmacological treatment for most patients with osteoporosis.
Administration: Oral weekly (alendronic acid, risedronate) or monthly (ibandronate); IV annually (zoledronic acid / Aclasta).
Clinical note: IV zoledronic acid is preferred for patients with GI intolerance to oral bisphosphonates, or where adherence with weekly/monthly oral regimens is a concern. Duration of treatment should be reviewed regularly with your consultant.
Denosumab
UK brand: Prolia
Mechanism: A monoclonal antibody that inhibits RANKL, preventing the formation and activation of osteoclasts. Comparable or superior bone density gains to bisphosphonates in head-to-head trials.
Administration: Subcutaneous injection every 6 months.
Clinical note: Unlike bisphosphonates, denosumab’s effect is reversible on discontinuation — a rapid rebound in bone resorption has been reported after stopping. Sequential antiresorptive therapy should be planned with the consultant before commencing.
Raloxifene
UK brand: Evista
Mechanism: A selective oestrogen receptor modulator (SERM) that mimics oestrogen’s beneficial effects on bone density in post-menopausal women without stimulating breast or uterine tissue.
Administration: Oral daily.
Clinical note: Reduces vertebral fracture risk in post-menopausal women. Less effective for non-vertebral fractures than bisphosphonates.
Hormone Replacement Therapy (HRT)
UK brand: Various preparations (Estradiol, combined preparations)
Mechanism: Oestrogen supplementation maintains and can modestly improve bone density in post-menopausal women by preserving oestrogen’s inhibitory effect on osteoclast activity.
Administration: Transdermal patches, gel, or oral preparations; combined with progesterone for women with an intact uterus.
Clinical note: Benefit for bone health is greatest when HRT is commenced at or near menopause. Individual benefits and risks, including cardiovascular and breast cancer considerations, should be assessed with the consultant.
Anabolic Group
Teriparatide
UK brand: Forsteo
Mechanism: A synthetic fragment of parathyroid hormone (PTH 1–34) that stimulates osteoblast activity, promoting new bone formation. The first licensed anabolic treatment for osteoporosis.
Administration: Daily subcutaneous self-injection for up to 24 months.
Clinical note: Indicated for patients with severe osteoporosis, very low T-scores, multiple vertebral fractures, or inadequate response to antiresorptive therapy. Followed by antiresorptive treatment after the anabolic course to consolidate BMD gains.
Romosozumab
UK brand: Evenity
Mechanism: A monoclonal antibody that inhibits sclerostin, simultaneously stimulating bone formation and inhibiting bone resorption — a dual mechanism unique among osteoporosis therapies.
Administration: Monthly subcutaneous injection for 12 months.
Clinical note: Approved for post-menopausal women at high fracture risk. Produces rapid and large BMD gains in both spine and hip.
A Note on Sequential Therapy
For many patients with osteoporosis, the most effective long-term strategy involves a planned sequence of treatments rather than a single agent. Anabolic therapy is often used first to build new bone, followed by antiresorptive treatment to preserve the gains achieved. The specific sequence — and the duration of each phase — is determined by the individual patient’s clinical profile, bone density trajectory, fracture history, and tolerability.
Treatment holidays, sequential switching, and combination approaches are all part of the modern management toolkit for osteoporosis. Your consultant will discuss the most appropriate treatment strategy for your specific situation at each review appointment.