Osteoporosis Drugs: Risk to the Heart?
Fosamax, Other Bisphosphonate Drugs Studied; No Reason to Stop Use, Experts Say
April 28, 2008 -- The osteoporosis drug Fosamax may be linked to increased risk of abnormal
heart rhythms, a new study shows. But experts urge patients not to quit Fosamax
or similar osteoporosis drugs based on the findings.
"We're not saying that this drug should be stopped and we certainly do
not feel that patients should stop taking the drug," researcher Susan
Heckbert, MD, PhD, tells WebMD. "But we did detect this adverse
The FDA has been probing possible ties between bisphosphonate drugs, which
include alendronate (sold generically and as Fosamax), and an irregular heart rhythm
(atrial fibrillation) since last fall, with no firm
conclusions yet. So what's an osteoporosis patient to do?
"The benefits of fracture prevention will generally outweigh the risk of
atrial fibrillation" in patients at high risk of bone fracture who are
already taking a bisphosphonate drug, says Heckbert, who works for the
University of Washington's cardiovascular health research unit and epidemiology
"What physicians and patients need to do is to weigh the risks and
benefits," Heckbert says. "The information is never perfect for
patients or physicians. ... They can't find out exactly what the risk is for
that individual patient, so they have to do the best job they can with the
available information. And this is just additional information about a risk
that appears to be present for alendronate."
Atrial Fibrillation Study
Heckbert's study, published in the Archives of Internal Medicine,
included 719 women with confirmed atrial fibrillation and 966 women without
atrial fibrillation. All of the women were members of the same health care
system in Washington.
The researchers checked the women's medical records and found that 6.5% of
the atrial fibrillation patients and about 4% of women without atrial
fibrillation had taken Fosamax.
Compared with women who had never used any bisphosphonate drug, women who
had ever taken Fosamax were 86% more likely to have atrial fibrillation.
Still, Fosamax wasn't a major risk factor for atrial fibrillation. "In
this population of women, the proportion of atrial fibrillation cases that
could have been explained by alendronate use was only 3%," Heckbert
The study doesn't prove that Fosamax caused atrial fibrillation. The study
was observational, meaning that patients weren't randomly assigned to take
The results held when the researchers weighed other heart rhythm risk
factors. "It was a robust finding," says Heckbert, cautioning that
observational studies can't address
every possible influence on the data.
Heckbert and colleagues did the study after other researchers last year
reported an increased rate of atrial fibrillation associated with the
osteoporosis drug Reclast, which, like Fosamax, is a bisphosphonate.
But in another recent study, Danish researchers found no evidence of
increased risk of atrial fibrillation in women taking bisphosphonates.
"Medicine is like that," Heckbert says. "We don't always
find the same things."