Women's Health: Benefits of a Major Osteoporosis Drug Last a Long While
Postmenopausal women who take alendronate, better known as Fosamax, to prevent osteoporosis may reap bone benefits for years after they go off the drugs. According to a study published in the current issue of the Journal of the American Medical Association, women who stop taking Fosamax have no greater risk of fractures up to five years later. Participants took the drug for five years on average before entering the study and were then randomly divided into three groups: Two groups got high or low doses, while one group got a placebo for five years. The study was funded by Merck, manufacturer of Fosamax.
"We found that women who continued to use the drug could do so safely, while retaining their bone mass," says study leader Dennis Black, a professor of epidemiology and biostatistics at the University of California–San Francisco. "Those who stopped taking it lost only a moderate amount of bone." Yet the rate of bone loss increased gradually over time, reaching pre-treatment levels toward the end of five years, he adds. This means that women may need to go back on the drug after a five-year hiatus.
Fosamax works by slowing down the production of bone-eroding cells, which allows bone-building cells to work more effectively, and is now given as a weekly pill of 70 mg costing about $60 to $70 per month. Interestingly, the researchers found no difference in bone mass or fracture risk between those who took the standard dose and those who took half that amount. Thus, some women might be able to go on a lower weekly dose of 35 mg, suggests Black.
The study did find that the risk of one type of rare spinal fracture was double in those who stopped taking the drug. "For women with a previous history of spinal fractures, this is pretty strong evidence that they should continue on the drug without taking a break," says Black. Anyone not at increased risk and with only moderate bone loss can probably go off Fosamax every five years, though this decision should be made in consultation with a doctor.
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