Bisphosphonates in bone diseases

Bisphosphonates are a class of drugs which are strongly attracted to the bone where they influence the calcium metabolism, mainly by inhibition of the osteoclast-mediated bone resorption. This property makes these compounds suited for the treatment of several diseases of the bone. In Paget's disease, several bisphosphonates can reduce bone pain and decrease the bone tumor 60- 70%. Cyclical oral etidronate and daily oral alendronate both proved to reduce the vertebral fracture rate for postmenopausal osteoporotic woman, while most investigated bisphoshonates can increase spinal bone mass in osteoporosis. Bisphosphonates can help lowering serum calcium and reverse skeletal complications in malignancy mediated bone diseases. Oral and intravenous administration of therapeutic doses is relatively safe. In general, gastrointestinal disturbances are described most often and the oldest, least potent, bisphosphonate etidronate can induce osteomalacia. The various characteristics of bisphophonates: phsycochemical, biological, therapeutic and toxicological, vary greatly depending on the structure of the individual bisphosphonate. Even small changes in the structure can lead to enormous differences in potency. Overall, this class of drugs offers several prospects of the future.