USE OF BISPHOSPHONATES IN THE TREATMENT OF OSTEOPOROSIS

Objective: To describe the mechanisms of action of bisphosphonates in the treatment of osteoporosis and compare bisphosphonate therapy with other treatments. Options: The bisphosphonates, etidronate, alendronat e, clodronate, pamidronate, tiludronate, ibandronate and risedronate; combined bisphosphonates and estrogen; combined bisphosphonates and ca lcium supplements. Outcomes: Fracture and loss of bone mineral density in osteoporosis; increased bone mass, prevention of fractures and imp roved quality of life associated with bisphosphonate treatment. Eviden ce: Relevant clinical studies and reports were examined with emphasis on recent controlled trials. The availability of treatment products in Canada was also considered. Values: Reducing fractures, increasing bo ne mineral density and minimizing side effects of treatment were given a high value. Benefits, harms and costs: Treatment with bisphosphonat es may be an acceptable alternative to ovarian hormone therapy in incr easing bone mass and decreasing fractures associated with osteoporosis . Compared with estrogens, bisphosphonates are bone-tissue specific, h ave equal or greater antiresorptive effect and have few side effects a nd no known risk for carcinogenesis. They also hold promise in treatin g male osteoporosis and steroid-induced bone loss. Prolonged, continuo us treatment with etidronate may lead to impaired calcification of new ly formed bone; therefore, etidronate is administered cyclically. This risk is not present in newer generations of bisphosphonates. Recommen dations: Bisphosphonate therapies may be considered as an alternative to ovarian hormone therapy in postmenopausal osteopenic or osteoporoti c women who cannot or will not tolerate ovarian hormone therapy. They should also be considered in treating male osteoporosis and steroid-in duced bone loss. Combination therapy with estrogen may be effective, a lthough more research is needed. Combination therapy with calcium supp lements is recommended. Bisphosphonate therapies should be restricted to postmenopausal patients with osteopenia or established osteoporosis and are not yet recommended for younger perimenopausal women as proph ylaxis. Validation: These recommendations were developed by the Scient ific Advisory Board of the Osteoporosis Society of Canada at its 1995 Consensus Conference. The Health Protection Branch, Canada, has approv ed etidronate and alendronate in the treatment of osteoporosis, and cl odronate has been approved in Canada for the treatment of hypercalcemi a-complicating malignancy. Sponsors: Sponsors of the 1995 conference i ncluded the Dairy Farmers of Canada, Eli Lilly Canada, Inc., Hoffmann- La Roche Canada Limited, Merck Frosst Canada Inc. and Proctor & Gamble Pharmaceuticals Canada Inc. Additional support to assist with publica tion was provided by Proctor and Gamble Pharmaceuticals Canada Inc.