Fosamax Break Won't Up Fracture Risk

(WebMD)  After five years of taking the osteoporosis drug Fosamax, some women will be getting a break.

That's "break" as in "drug holiday," not as in "fracture." A U.S. clinical trial shows that women who stop taking Fosamax after five years have no more fracture risk than women who keep on taking the drug.

Women who stopped taking Fosamax had a little bit more bone loss than women who kept taking it. But this increased bone loss wasn't meaningful.

"For many women, discontinuation of [Fosamax] for up to five years does not appear to significantly increase fracture risk," concludes Dennis M. Black, PhD, of the University of California, San Francisco, and colleagues in the Dec. 27 issue of The Journal of the American Medical Association.

Fosamax is a member of a family of drugs called bisphosphonates. Other members of this family are Actonel and Boniva.

"It appears that for some women, five years of bisphosphonate therapy may be enough to realize fracture reduction benefits," notes Duke University researcher Cathleen S. Colón-Emeric, MD, in an editorial accompanying the study.

There was a slightly increased risk of spine fracture, so women who've had previous vertebral fractures shouldn't stop taking Fosamax.

"Women at very high risk of clinical vertebral fractures may benefit by continuing beyond five years," Black and colleagues suggest.

No woman taking Fosamax should stop taking the drug without talking to her doctor. Even if a doctor says it's OK to take a Fosamax holiday, close monitoring is needed.

Fosamax, Osteoporosis, and Fracture Risk

The study by Black and colleagues is an extension of one of the clinical trials that led to Fosamax's approval. In the extended study, 329 women continued taking Fosamax after five years of treatment. An additional 437 women who'd taken Fosamax for five years got identical looking, inactive placebo pills for the next five years.

The women who stopped taking Fosamax averaged 2.4% lower bone density at their hip and 3.7% lower bone density at their spine. But in both places, their bone density remained higher than before they started Fosamax treatment 10 years earlier.

Moreover, a look at how many women got hip fractures showed no increased risk from stopping Fosamax. However, women who continued taking Fosamax had fewer spinal fractures.

In her editorial, Colón-Emeric notes that it's still not clear when -- or whether -- women who take a Fosamax "holiday" should resume taking the osteoporosis drug.

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SOURCES: Black, D.M. The Journal of the American Medical Association, Dec. 27, 2006; vol 296: pp 2927-2938. Colón-Emeric, C.S. The Journal of the American Medical Association, Dec. 27, 2006; vol 296: pp 2968-2969.

By Daniel DeNoon
Reviewed by Brunilda Nazario