Researchers have recently linked the drug Fosamax (Alendronate) to an increased risk for women of developing an irregular heartbeat. A US study suggested that the pharmaceutical, which is prescribed across the globe to halt bone thinning in women, may lead to a condition called atrial fibrillation.

While atrial fibrillation is not always serious, it can lead to stroke for some. The Archives of Internal Medicine conducted a similar study, had concluded that for the majority of women taking Fosamax the benefits of the drug outweighed the potential risks.

Fosamax, produced by pharmaceutical giant Merck, as well as the generic alendronate, has been researched quite a bit in the last few years. The worst results came recently, which suggested that the drug may increase the risk of atrial fibrillation by as much as 86 percent. In most cases, the condition has no noticeable symptoms. However, it can make the patients more susceptible to blood clots, which in turn can lead to an embolic stroke.

“Having ever used alendronate was associated with an 86 percent higher risk of newly detected atrial fibrillation compared with never having used the drug,” said Dr. Susan Heckbert of the Group Health Center for Health Studies and leader of the research.

“Careful judgment is required to weigh the risks and benefits of any medication for any individual patient. For most women at high risk of fracture, alendronate’s benefit of reducing fractures will outweigh the risk of atrial fibrillation,” she added.

When contacted for comment, the National Osteoporosis Society said that the results of this study were “interesting, but should be considered in the context with other recent research, which has not shown the same increase in atrial fibrillation.”

“Fosamax is highly effective at reducing someone’s risk of experiencing a fracture due to osteoporosis,” Merck spokeswoman Sarah Leyland said.

Other side effects of Fosamax.