Repurposing erectile dysfunction drugs tadalafil and vardenafil to increase bone mass

Significance Tadalafil and vardenafil are among the most widely used drugs for erectile dysfunction, which affects nearly 19% of men over 20 y of age. Older men also suffer from age-related bone loss resulting in crippling fractures. We show that in mice, both agents act on bone cells, resulting in the formation of new bone and reduced removal of old bone. Because of this net gain in bone mass, we posit that tadalafil and vardenafil could be used for cotreating erectile dysfunction and osteoporosis in men of advancing age, as well as for treating osteoporosis in postmenopausal women. We recommend future clinical studies to establish the capability of these drugs to increase bone density and reduce fracture risk in humans.