Bisphosphonates reduce bone breakdown and fracture risk in osteoporosis, which is strongly supported by multiple studies. The effect persists for some time after stopping. The rare side effect of jaw bone necrosis is mainly relevant at high doses in cancer patients, and less so at low oral doses for osteoporosis. Despite good evidence, these drugs are in practice far too rarely prescribed after a hip fracture.
Bisphosphonates inhibit bone breakdown by targeting the cells that break down bone, the osteoclasts. The drugs bind to bone mineral and are taken up by these cells, after which the osteoclasts die through programmed cell death. The result is that the balance between bone breakdown and bone formation shifts: the bone loses less mass.
The evidence that bisphosphonates genuinely prevent fractures in people with osteoporosis is strong. Research covering treatment periods of up to ten years shows that the benefit-to-risk ratio is favourable for people with a high fracture risk. That is no small point: international research across 19 countries shows that after a hip fracture, 14 to 28 percent of patients die within a year, depending on the country. Preventing that first fracture is therefore medically significant.
In people who use corticosteroids long-term, such as prednisone, those drugs substantially weaken the bone. Oral bisphosphonates are recommended as the first choice in that situation, preferably combined with vitamin D and calcium. Bone mineral density demonstrably increases, but the evidence that this directly leads to fewer fractures in this specific group is less complete than it is for ordinary osteoporosis.
One distinctive feature of bisphosphonates is that the effect does not stop as soon as you stop taking the pill. The substances remain locked in the bone mineral for years and are only released gradually. The bone-protective effect therefore persists for some time after treatment is discontinued, which makes bisphosphonates different from other drugs such as denosumab, where the effect disappears quickly after stopping.
The best-known serious side effect is osteonecrosis of the jaw: bone tissue in the jaw that dies off. This is rare, but the risk is considerably higher in cancer patients receiving high intravenous doses than in osteoporosis patients taking low oral doses. The mechanism has not yet been fully explained. A dental check-up before the start of treatment and good oral hygiene during treatment are routinely recommended.
Despite the evidence for the effectiveness of bisphosphonates, internationally only 11 to 50 percent of patients actually receive preventive medication after a hip fracture. Men are overlooked even more systematically than women in this regard. This is a treatment gap that is large, and where the benefit of better follow-through would be considerable.
All claims are based on PMID sources supplied by the editorial team (including clinical guidelines, observational international research and mechanistic work). No external knowledge was used.