ast week, a federal advisory panel urged
regulators to warn parents that antidepressant drugs not only
increase the risk of suicide in some children, but that most have a
poor track record in curing their disease.
The recommendation came after a yearlong debate over whether the
drugs are as safe and effective as advertised. It was based on
evidence that a small minority of children show increased signs of
suicidal behavior when taking the drugs.
Through it all, one of the drugs seemed somehow above the fray:
Although the warning is recommended for Prozac as well as other
drugs, Prozac is still the only one approved by the Food and Drug
Administration for the treatment of depression in children and
adolescents. A large government-financed trial recently found that
it worked better than talk therapy in helping teenagers overcome
depression. And when British health officials announced a sweeping
ban of antidepressant use in children, which touched off the debate
last year, they specifically exempted Prozac.
But is it really that different?
The short answer is no, experts say. Although chemically distinct
from other drugs in the same class, Prozac works on precisely the
same principle, they say, and there's no evidence that it is
significantly safer or more effective than the others in treating
childhood depression. Prozac has shown in several trials that it can
relieve depression in youngsters and adolescents significantly
better than dummy pills. Such convincing evidence is not available
for the other drugs. But, research psychiatrists say, that does not
mean the other drugs in the same family do not work in young people,
only that they have not been properly tested.
"It makes no scientific sense that you would find any significant
difference in the effects" of these drugs, said Dr. Steven Hyman, a
Harvard psychiatrist and former director of the National Institute
of Mental Health, who is not a consultant for antidepressant makers.
"All target and bind to the same molecule in the brain."
Dr. John M. Plewes, a medical adviser at Eli Lilly, which makes
Prozac, disagreed that the differences were minimal. "We've got very
good data that the drug is safe and effective in children, and no
other drug has this kind of data," he said.
The molecule these drugs bind to is the one the body uses to
dampen the activity of a mood-altering brain chemical called
serotonin, Dr. Hyman said. When this molecule is tied up by a drug,
serotonin surges lasts longer and, over time, improve mood in some
people who are depressed. Prozac was the first antidepressant drug
on the market to work primarily on serotonin, and the others that
came later - including Paxil, from GlaxoSmithKline; Zoloft, from
Pfizer; and Celexa, from Forest Laboratories - are what some
researchers consider copycat or me-too drugs.
Prozac does linger in the body longer than the others do, once
people stop taking it, psychiatrists say. This makes withdrawal more
gradual than from other antidepressants, and keeps levels of the
drug steady if people miss doses. Teenagers in particular often
forget or skip doses, child psychiatrists say, and many of these
psychiatrists believe that the potential for suicide is highest in
people being treated when their dosage is changing, up or down.
One recent analysis of records of patients who had taken
antidepressants, including some 160,000 adults and children, found
that the suicide risk was highest in the first three to four weeks
of treatment. But no one has shown convincingly that there are
significant differences among the drugs, or determined exactly what
the withdrawal risks are.
"You really need to watch young patients on these drugs closely
at all times," said Dr. John March, chief of the division of child
and adolescent psychiatry at Duke University Medical School, the
lead author of the recent study comparing Prozac to talk therapy.
Dr. March has been a consultant to Pfizer and other drug makers but
currently receives almost all his research financing from the
government, he said.