Strontium ranelate: the first agent of a new therapeutic class in osteoporosis

Strontium ranelate is a new agent developed for the management of post-menopausal osteoporosis. It has a unique mode of action, based on an uncoupling between bone formation (increased) and bone resorption (decreased). To review its effectiveness we searched the MEDLINE database from 1985 to 2008, as well as databases such as the Cochrane controlled register, for citations or relevant articles. After this extensive search of the literature, a critical appraisal of the data was obtained through a consensus meeting (AN, MH, SS, OB, and J-YR). We found that strontium ranelate reduces vertebral, nonvertebral, major nonvertebral, and hip fractures over 1, 3, 4, and 5 years. Its spectrum of activity covers women with osteopenia, osteoporosis, and severe osteoporosis. Elderly subjects also show a reduction in vertebral and nonvertebral fractures. Bone mineral density may be used as a monitoring tool for strontium ranelate, since early changes are predictive of long-term fracture reduction. Biochemical markers of bone turnover reflect the uncoupling between resorption and formation. The safety profile of strontium ranelate compares favorably with the other currently marketed antiosteoporosis medications. Preliminary results suggest that strontium ranelate is able to reduce the progression of spine osteoarthritis. In conclusion, strontium ranelate has the potential to be a candidate for first-line treatment of osteopenia and osteoporosis. However, further research is needed before suggesting its widespread use in osteoarthritis.