MONDAY, March 21, 2005 (HealthDayNews) -- Of the nearly 1 million people who are hospitalized each year for congestive heart failure, about 10 percent are given the drug nesiritide (Natrecor), but a new report questions the long-term safety of this popular medication.

"Our concern is that this drug has substantial risks," said researcher Dr. Keith Aaronson, an associate professor in the Division of Cardiovascular Medicine at the University of Michigan. "A study needs to be done to see whether this drug is safe."

A review of several clinical trials found a 40 percent to 50 percent increased risk of kidney problems when nesiritide is given to patients with congestive heart failure, according to the report in the March 29 issue of Circulation.

The maker of the drug said this latest study raises no new points.

The review describes an effect that Scios Inc. and the U.S. Food and Drug Administration are already aware of, said Dr. Darlene Horton, the company's senior vice president for clinical research and medical affairs. "This is a well-known phenomenon with Natrecor," she said, adding that the labeling on the drug reflects that knowledge.

At recommended doses, Natrecor has not caused any increases in kidney failure or death, Horton said. "We have looked at these patients who have had increases in creatinine [a measure of kidney function], and we know that there was no increase in worse outcomes. There was no need for dialysis, and there was no increase in mortality in these patients," she said.

Horton added that Scios is currently involved in trials looking at the effect of Natrecor on creatinine levels. "More recent data has suggested that Natrecor has a protective effect in patients with renal insufficiency," she said.

The data in this latest study shouldn't cause any changes in how the drug is used, Horton said. "This Circulation article should have no impact on clinical practice, since the facts discussed in the article are already on the product label," she explained.

Heart failure is a common problem affecting some 5 million Americans, with more than a half million new cases diagnosed each year, according to the American Heart Association.

Signs of congestive heart failure include fluid build-up in the lungs, called pulmonary edema, and fluid build-up in the legs, called peripheral edema. Symptoms include shortness of breath during exertion and shortness of breath when lying down.

The usual first-line therapy is diuretics, which help by reducing the amount of water the patient retains. Natrecor is a powerful medication given intravenously, usually after other treatments have failed, that quickly relieves a patient's discomfort.

"This drug should not be first-line therapy, but reserved for those for whom standard therapy proves inadequate," Aaronson said.

Lead study author Dr. Jonathan Sackner-Bernstein, director of clinical research at the Heart Failure and Cardiomyopathy Center at North Shore University Hospital in New York, believes these new findings should be taken seriously.

"This is an important study, because prior investigations have shown that if there is worsening kidney function during hospitalization for heart failure, it is a sign of a person who is at markedly higher risk of dying in the following weeks to months," he said.

In their study, Sackner-Bernstein and his team collected data on 1,269 heart failure patients who participated in five clinical trials comparing Natrecor with other drugs.

"We found that there is a 40 to 50 percent higher risk of worsening kidney function when people are treated with nesiritide than when people are treated with other medications," Sackner-Bernstein said. "This has important implications for the potential risk that might be associated with this drug that has not yet been studied in formal outcomes trials."

Sackner-Bernstein believes studies are needed to determine whether there is an increase risk of death in patients who receive Natrecor. "We can't tell that from our data or from the available data," he said. "But this would be suggestive that this is a possibility that needs to be explored."

Doctors who use Natrecor should realize there may be some real risks associated with the drug, Sackner-Bernstein said. "I hope clinicians would look at these data and realize that they really need to think twice before administering this drug and, until there is a definitive trial, they should consider using other therapies first and reserve nesiritide for when other therapies prove inadequate," he said.

Dr. Wilson S. Colucci, director of the cardiomyopathy program at Boston University School of Medicine, said this finding is important, but does not require a change in clinical practice.

"It raises a red flag," Colucci said. However, "at this point, this study has not demonstrated that these changes in renal function are actually associated with poor outcomes," he added.

"I don't believe nesiritide is first-line treatment," he said. "That's why these findings have relatively little impact on the way I recommend its use. I have always viewed nesiritide as an extremely good second agent when the patient hasn't responded well to diuretics."

"If one were talking about using nesiritide as a first-line drug, then the findings would cause me more concern," Colucci said.

More information

The American Heart Association can tell you more about heart failure.

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