TUESDAY, Jan. 27 (HealthDay News) -- The short-term use of heart failure drugs called loop diuretics does not appear to increase the risk of fractures in postmenopausal women, a new study finds, but their effect over the long term is less clear.

Loop diuretics include widely used medicines such as Lasix, Bumex and Demadex, which are commonly prescribed to patients with congestive heart failure. Because these medications increase the loss of calcium, there has been a concern that they might reduce bone mineral density, increasing users' risk for fractures.

However, "much of the association that may have been blaming loop diuretics may have really been a result of the other health problems that women had," said study co-author Dr. Karen Johnson, vice chairwoman of the department of preventive medicine at the University of Tennessee Health Science Center, in Memphis.

Johnson believes that doctors should still pay attention to bone mineral density when starting women on loop diuretics. "You probably want to make sure people are following the recommendations to prevent osteoporosis, including taking calcium and vitamin D supplements," she said.

The report is published in the Jan. 26 issue of the Archives of Internal Medicine.

For the study, Johnson's group collected data on almost 134,000 American women who participated in the Women's Health Initiative from October 1993 to December 1998. During 7.7 years of follow-up, the researchers recorded all falls and fractures reported by the women.

Among the women, more than 3,400 were taking loop diuretics. The researchers found no significant association between loop diuretics and fractures, including hip fractures, spine fractures and falls.

However, there did appear to be a small increase in fractures among women who took loop diuretics for more than three years, Johnson noted.

Women should ask their doctor which diuretic they are taking, because not all diuretics are loop diuretics, Johnson said. Women should also ask about their bone mineral density to determine whether they are at risk for osteoporosis and fractures, she said.

Dr. Jeffrey S. Berger, a cardiologist at Duke University Medical Center and an expert in women's heart health, doesn't think the study is definitive. He said the long-term use of loop diuretics could still result in an increased risk of fracture.

"One has to be careful when prescribing medications such as loop diuretics," Berger said. "Medications may have harmful side effects. It is important to keep patients on the medication for as short a time as they need to be on it."

Berger stressed that loop diuretics are effective and important drugs for heart patients. "They help a lot more than they harm," he said. "They are useful and they make people feel a lot better, especially those with bad heart failure."

Still, "this study should raise a red flag," Berger said. "One has to be mindful of potential side effects, in this case it's fractures with the long-term use of loop diuretics."

Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, agreed that the study is not the last word on the subject.

"It is important to note that the dose of loop diuretics were not collected [in the study] and even among the women reported to have heart failure there was minimal use of guideline-recommended heart failure medications." Fonarow said. "As such, it is unlikely this study involved many patients on higher doses of loop diuretics or with moderate to severe heart failure."

That means that, "there is a need for further studies to determine if moderate- or high-dose loop diuretic use is associated with bone fractures and falls," Fonarow said.

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