Benefits,
risks of heart failure drug questioned
(This article was first printed in the August
2005 issue of the Harvard Heart Letter.
For more information or to order, please go
to www.health.harvard.edu/heart.)
The jury is still out on who needs nesiritide,
a heart failure drug, as well as what its risks
are.
A drug designed to ease heart failure flare-ups
has come under fire because it may harm the kidneys
and cause premature death. The drug, nesiritide
(Natrecor), was approved by the FDA in 2001 for
treating people in the midst of a heart failure
crisis who were hospitalized because they had
trouble breathing. An infusion of the drug quickly
and effectively makes it easier to breathe.
Nesiritide (neh-SEAR-eh-tide) became a hit with
many doctors, even though at $500 an infusion
it costs far more than diuretics and other inexpensive
drugs that often work just as well. Some doctors
also started using it as a kind of routine tune-up
for people with serious but stable heart failure.
As of mid-2005, an estimated 600,000 people have
been treated with nesiritide.
What nesiritide does
Heart failure is a collection of problems that
stem from the heart’s inability to meet
the body’s need for oxygenated blood. The
most common symptoms are trouble breathing and
swollen legs. These are caused by blood pooling
in the lungs and legs. Other symptoms include
fatigue and trouble exercising or carrying out
daily activities.
Drug therapy, careful attention to what you
eat and drink, exercise, rest, and other lifestyle
changes can help keep heart failure under control.
Symptom flare-ups tend to occur when you skip
medications or stray too far from your diet.
But they can also happen even if you stick with
your heart failure management plan. Flare-ups
(what doctors call heart failure decompensation)
can land you in the hospital, often struggling
to breathe.
Nesiritide is a manufactured version of a hormone
the heart makes when it is under stress, called
B-type natriuretic peptide (BNP). The drug (like
the hormone) relaxes and widens blood vessels.
It also reduces pressure inside the upper chambers
of the heart. This combination makes it easier
for the heart to move blood through the body,
and for blood to return to the heart from the
lungs and legs.
Keeping heart failure
under control
If you have heart failure, some simple
strategies can keep it from flaring up
and keep you out of the hospital:
- Take your medications, even when you
are feeling fine.
- Stick with your diet.
- Go easy on the salt.
- Drink the right amount of fluid.
- Weigh yourself every day.
- Have your potassium checked.
- Exercise regularly.
- Relax and reduce stress.
- Guard against the flu and pneumonia.
- Watch out for signs of a flare-up.
These include sudden weight gain; shortness
of breath at rest, with activity, or
when lying down; and unusual fatigue
or swelling.
|
Under fire
Two studies from one research team challenge
the widespread use of nesiritide. Both used data
from trials the FDA relied on to approve the
drug, all of which included people who got nesiritide
for a heart failure crisis. In the first study,
published in Circulation, 21% of people
who got nesiritide developed warning signs of
kidney trouble, compared with 15% who got a placebo.
In the second study, published in the Journal
of the American Medical Association (JAMA),
7.2% of those who received nesiritide died within
a month of treatment, compared with 4% of those
who got a placebo.
The researchers, from hospitals in New York
and Michigan, call for a large trial designed
specifically to look at nesiritide’s effects
on the kidney and survival. Until then, they
recommend that it be used only as a backup when
older drugs don’t work.
What this means for you
The recommendation to use other drugs first
for heart failure flare-ups makes good sense,
says Dr. Eldrin F. Lewis, a heart failure specialist
at Harvard-affiliated Brigham and Women’s
Hospital. Intravenous versions of diuretics,
the “water pills” taken by millions
of Americans, work for most people having a heart
failure crisis. If they don’t, or if they
aren’t appropriate, and alternatives such
as nitroglycerin or nitroprusside aren’t
much help or can’t be used, then nesiritide
can be an important weapon.
The two studies raise a real red flag about
the routine use of nesiritide infusions to prevent
flare-ups in people with stable heart failure,
says Dr. G. William Dec, chief of cardiology
at Massachusetts General Hospital, another Harvard
teaching hospital. If a single infusion of nesiritide
does, indeed, increase the chances of kidney
trouble or premature death, then a series of
such treatments could, too.
Scios, the company that developed nesiritide,
has changed the label — the tiny-print
insert that accompanies all prescriptions — to
include information on mortality. It summarizes
data from seven trials (four more than the JAMA study)
that together show only a small difference in
death rates between nesiritide (5.3%) and placebo
(4.3%).
The company asked Dr. Eugene Braunwald, a pre-eminent
heart failure specialist and member of the Harvard
Heart Letter editorial board, to convene
an independent panel of experts to review the
data on nesiritide. The panel's recommendations
included:
1. Natrecor should be used only for people who
go to the emergency room or who are hospitalized
for severe shortness of breath due to heart failure.
2. The drug should not be used in the doctor’s
office or a clinic as a routine “tune-up” to
keep heart failure from getting worse.
If you have been getting routine infusions of
Natrecor, ask your doctor why. Make sure he or
she knows about the Braunwald report. So far,
there is no evidence that routine Natrecor infusions
work, and hints that they may do more harm than
good. A clinical trial is underway to sort out
who, if anyone, might benefit from a series of
Natrecor infusions.
(This article was first printed in the August
2005 issue of the Harvard Heart Letter.
For more information or to order, please go
to www.health.harvard.edu/heart.)
|
HOME
MY
CART
12
monthly issues
