Risedronate: a new oral bisphosphonate

Bisphosphonates have been effective in the treatment of osteoporosis and Paget's disease of bone. Risedronate, the newest oral bisphosphonate, is approved by the US Food and Drug Administration for the prevention and treatment of postmenopausal osteoporosis and glucocorticoid-induced osteoporosis and the treatment of Paget's disease of bone.

This article reviews current studies of risedronate in osteoporosis and Paget's disease of bone and, to the extent possible, compares risedronate with other bisphosphonates and other therapies. Information on the pharmacokinetics and adverse effects of risedronate, and the drug's use in other disorders, is also reviewed.

Clinical studies and review articles concerning the use of risedronate published in the English-language literature from 1966 through October 2000 were identified through searches of MEDLINE, PREMEDLINE, and International Pharmaceutical Abstracts using the search terms risedronate and NE 58095. Recent clinical studies, review articles, and consensus statements regarding the use of other bisphosphonates were identified through searches of the same databases for this period using the search terms bisphosphonates, alendronate, osteoporosis, and Paget's disease of bone.

The use of risedronate therapy in patients with postmenopausal osteoporosis has been shown to increase bone mineral density (BMD) and decrease the incidence of fractures compared with placebo. In glucocorticoid-induced osteoporosis, risedronate has been shown to increase BMD without having a consistently significant effect on the risk of fractures. Although there are no direct comparisons between bisphosphonates in glucocorticoid-induced osteoporosis, risedronate appears to be less effective than alendronate and more effective than etidronate in terms of effects on BMD and/or fracture risk. In Paget's disease of bone, risedronate has been reported to be more effective than etidronate in decreasing serum alkaline phosphatase levels and bone pain. Finally, risedronate has been associated with a lower incidence of gastric ulcers than alendronate.

In terms of efficacy in the prevention and treatment of osteoporosis and the treatment of Paget's disease of bone, risedronate is comparable to alendronate, the other orally available bisphosphonate. It appears to have better gastrointestinal tolerability than alendronate and may be preferred for patients in whom this is a concern. However, direct comparative and pharmacoeconomic studies are necessary to determine risedronate's relative place in the therapy of osteoporosis and Paget's disease of bone.