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Congestive heart failure, is a medical condition in which the heart
gradually loses the ability to pump blood. About 1 in 5 people with this
condition suffer flare-ups in which they gasp for breath and need hospitalization.
The Food and Drug Administratio has in August 2001, approved an injection
of Natrecor as a way to treat these acute flare-ups.
Natrecor, known chemically as nesiritide, is a bioengineered version of
a natural hormone that helps dilate blood vessels.
That dilation helps blood flow from the weakened heart. But it also can
cause seriously low blood pressure.Two years ago, the FDA rejected approval
of Natrecor because it caused so many cases of hypotension rates of 8
percent to 14 percent, depending on the dose used.
So manufacturer Scios Inc. tested a much smaller dose in another study
of 498 patients. This time, low blood pressure
struck only about 4 percent of patients.
That’s similar to the side-effect rate of nitroglycerin, another
common treatment for acute heart failure - so the FDA approved an injection
containing the lower Natrecor dose.
But doctors will have to use Natrecor carefully. Unlike when nitroglycerin
is used, the low blood pressure may not show up right away but within
four or five hours - and when it does strike, it can last longer, said
Dr. Douglas Throckmorton, FDA’s deputy director of cardiorenal drugs.
“You need to watch them longer,” Throckmorton warned physicians.
Studies showed patients could breathe better as blood circulation and
lung congestion improved with Natrecor treatment. But Throckmorton said
that Scios’ study was not designed to tell if Natrecor is any better
an option than the nitroglycerin often used today.
But it is a novel drug, the first bioengineered form of B-type natriuretic
peptide sold. California-based Scios said it will start shipping Natrecor
to hospitals this week; each vial, a day’s treatment, will cost $380.
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