Osteoporosis is characterized by reduced bone mass and disruption of bone 
architecture, resulting in increased fracture risk. Several therapeutic agents 
are now available to treat postmenopausal osteoporosis and prevent fractures. 
Combined calcium and vitamin D supplementation reduce the relative risk of 
non-vertebral fractures by about 18%. Hormone replacement therapy (HRT) should 
not be prescribed for osteoporosis in women who do not experience menopausal 
symptoms. The marked benefits of raloxifene on the reduction in invasive breast 
cancer and vertebral fracture risk are partially counterbalanced by a lack of 
effect on non-vertebral fracture risk, and an increased risk of venous 
thromboembolism and stroke. All four bisphosphonates available in Belgium, 
except ibandronate, have been shown to reduce the risk of vertebral, 
non-vertebral and hip fractures in prospective, placebo-controlled trials. 
Globally, the incidence of vertebral fractures is reduced by 41%-70%, and the 
incidence of non-vertebral fractures by 25%-39%. The anti-fracture efficacy of 
weekly or monthly doses of oral bisphosphonates has not been directly shown but 
is assumed from bridging studies based on BMD changes. To date, the various 
bisphosphonates have not been studied in head-to-head comparative trials with 
fracture endpoints. There are potential concerns that long-term suppression of 
bone turnover associated with bisphosphonate treatment may eventually lead to 
adverse effects, especially atypical femoral fractures and osteonecrosis of the 
jaw, but these cases are extremely rare. Teri-paratide (recombinant human 1-34 
PTH) administered by daily subcutaneous injections decreases by 65% the relative 
risk of new vertebral fractures in patients with severe osteoporosis. Pivotal 
trials with strontium ranelate have shown a 41% reduction in new vertebral 
fractures and a 16% reduction in non-vertebral fractures over 3 years. Denosumab 
is a fully human monoclonal antibody to RANK Ligand that is administered as a 
60-mg subcutaneous injection every 6 months. In the pivotal phase III trial, 
there was a 68% reduction in the incidence of new vertebral fractures, whereas 
the incidence of non-vertebral fractures was reduced by 20%. Several new 
approaches are being explored, including antibodies to sclerostin, cathepsin K 
inhibitors, src kinase inhibitors, and drugs that act on calcium sensing 
receptors.