Preventing bone loss, reducing risk

CLINICAL UPDATE – Osteoporosis: Osteoporosis is a condition of the bone itself, where the bone mass is reduced. The bones become weaker and more prone to fracture. Good evidence supports the treatment of patients with osteoporosis to prevent further bone loss.

There have been great developments in this sphere. “If there is an imbalance in activity in the bone between osteoblast cells which build up matrix (the protein scaffolding and its embedded calcium which make up the sturdy part of the bone) and those which break down matrix (osteoclasts), there can be a net reduction in bone mass,” said Prof Geraldine McCarthy, consultant rheumatologist at Dublin’s Mater Hospital.

Bisphosphates
“Bisphosphates would be firs- line medications for osteoporosis,” said Dr Malachi McKenna, Consultant in Endocrinology and Metabolism at St Vincent’s hospital in Dublin. Alendronate, risedronate and ibandronate are given orally.

There are also intravenous formulations that are useful for the ten per cent or so of patients who cannot tolerate the oral medication. Strontium ranelate or raloxifene are alternatives for postmenopausal women, if bisphosphonates are not suitable due to contraindications or intolerance.

Bone resorption
Drugs in osteoporosis act mainly on bone resorption (inhibiting osteoclasts) or on bone formation (stimulating osteoblast activity). Most studies have been conducted on postmenopusal (PM) women.

Bisphosphonates are potent inhibitors of bone resorption and are the most prescribed medication in the management of osteoporosis. All the authorised bisphosphonates (for example alendronate, risedronate, ibandronic acid, zoledronic acid and etidronate) reduce the risk of vertebral fractures.

Reduce the risk
Alendronate, risedronate and zoledronic acid have also been shown to reduce the risk of non-vertebral fractures including hip fractures. Bisphosphonates have been used in trials for up to 10 years, which suggest that bone quality remains normal and that reductions in fracture risk are sustained for as long as treatment continues. – Irish Medical Times