Treatment with tibolone, a drug with hormone-like effects, reduces the risk of fractures and the risk of breast and colon cancer in postmenopausal women with osteoporosis, but also seems to increase the risk of stroke, according to the results of the Long-Term Intervention on Fractures with Tibolone (LIFT) trial.

Conducted in North and South America, Europe, and Australia, LIFT included 4538 women 60 to 85 years of age with osteoporosis, according to the report in The New England Journal of Medicine. Women were excluded if they had a history of cancer, blood clots, or had used estrogen or other hormone-type drugs in the past.

Subjects were randomly assigned to daily treatment with tibolone or “inactive” placebo, lead author Dr. Steven R. Cummings, at the University of California, San Francisco, and colleagues note. All subjects also received calcium and vitamin D supplements.

During roughly 3 years of follow-up, tibolone users were less likely to break a bone than were subjects given placebo.

As noted, treatment with tibolone was also associated with decreased risks of breast cancer and colon cancer.

Although tibolone therapy did not increase the risk of blood clots as some others hormone-type drugs have been known to do, it more than doubled the risk of stroke relative to placebo.

In light of these findings, Cummings’ group advises that tibolone “should not be used in elderly women” or “in women who have strong risk factors for stroke, such as (high blood pressure), smoking, diabetes, and atrial fibrillation,” a common, abnormally fast heart beat.

SOURCE: The New England Journal of Medicine, August 14, 2008.