Men's Osteoporosis Support Group

Two-year comparison of Fosamax vs. Actonel

Int J Clin Pract. 2008 Apr;62(4):575-84, A comparison of the effect of alendronate and risedronate on bone mineral density in postmenopausal women with osteoporosis: 24-month results from FACTS-International. Reid DM and others. PMID: 18324951. This study was a one-year extension of a previous FACTS international comparison trial in postmenopausal women using either 70-mg Fosamax (alendronate) or 35-mg Actonel (Risedronate), each taken once-weekly (OW). Effectiveness of the two therapies was based upon multiple variables: BMD of hip trochanter, lumbar spine, total hip and femoral neck along with levels of four bone turnover markers. The results showed a greater increase in the hip trochanter, and other hip sites, with alendronate than risedronate. Additionally there were larger decreases in bone turnover markers with alendronate than risedronate. The authors conclude, "Alendronate 70 mg OW yielded significantly greater BMD gains and larger decreases in bone turnover maker levels than risedronate 35 mg OW over 24 months, with no difference in UGI tolerability."

Editor's comments. Note that these results are in line with those from another article mentioned in a 2006 Update. When I reviewed that article my feelings were that greater bone density and more greatly reduced bone turnover were the ideal goal of bisphosphonate osteoporosis therapy. After the recent Update articles on osteonecrosis of the jaws (ONJ), I'm not so sure that maximum increases in bone density and decreases in bone turnover are ideal after all. That is, it appears that decreasing bone turnover too much makes some individuals more susceptible to ONJ, a complication of bisphosphonate therapy for osteoporosis for which we don't yet know all the answers. There are, in fact, some who are recommending "drug holidays" in which bisphosphonate therapy would be stopped for a year or two (perhaps every four or five years) to let the bone turnover rate return to higher levels as a means of decreasing the risk of ONJ and atypical fractures of the femur, as noted in the previous Update this month. So this is an evolving story, one for which close monitoring is prudent for all of us taking bisphosphonates. Like the old children's story, the slow steady tortoise might get better results than the speedy rabbit when it comes to rebuilding lost bone mineral density.

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