For the prevention of fractures, antiresorptive drugs (bisphosphonates and 
denosumab) that decrease high bone resorption and, secondarily, also bone 
formation, are the mainstream of therapy. Osteoanabolic drugs, such as 
teriparatide, increase bone formation more than bone resorption, and are used in 
severe osteoporosis, including patients treated with antiresorptive drugs who 
still lose bone and have recurrent fractures. New potential drugs for fracture 
prevention that uncouple bone resorption from bone formation include odanacatib, 
a specific inhibitor of cathepsin-K, the enzyme that degrades bone collagen type 
I, that inhibits bone resorption and only temporarily bone formation, and 
monoclonal antibodies against sclerostin (romosozumab, blosozumab), that 
stimulate bone formation and decrease bone resorption.