Established and forthcoming drugs for the treatment of osteoporosis.

Nowadays, effective drugs are available to prevent fractures in patients at high risk for osteoporotic fractures. The generic bisphosphonates alendronate and risedronate are first choice, because of their effectiveness and tolerability in the majority of patients, while they also have a low cost price. However, the use of bisphosphonates can be associated with side effects: not only the well-known (upper) gastrointestinal side effects, but also (spontaneous) atypical fractures of the femur and aseptic necrosis of the jaw. Denosumab and zoledronic acid are both potent antiresorptive drugs that could be an attractive alternative for those patients who do not tolerate oral bisphosphonates. Strontium ranelate has both antiresorptive and anabolic effects, while teriparatide has primarily anabolic effects. The working mechanism of cathepsin K inhibitors and monoclonal antibodies against sclerostin, both currently under development, is exciting since the usually occurring coupling of bone resorption and bone formation has not been found so far.