Healthy Skepticism Library item: 6999

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Publication type: news

Mundell EJ.
Common PTSD Drug May Be Useless: Study finds guanfacine offers no benefit and carries risks.
HealthDay News 2006 Dec 1

Abstract:

A drug long used to treat post-traumatic
stress disorder appears to have done patients no good and may even have done
some harm.

In the first-ever randomized, placebo-controlled trial of guanfacine for the
alleviation of post-traumatic stress disorder (PTSD), “we found that it
really offered patients no benefits of any symptoms, and we looked at a lot
of symptoms,” said lead researcher Dr. Thomas Neylan, medical director of
the PTSD treatment program at the San Francisco VA Medical Center.

“We looked at whether people were feeling less anxious, whether they were
sleeping better, whether they startled less, whether they were having fewer
intrusive memories,” said Neylan, who is also an associate professor of
psychiatry at the University of California, San Francisco. “But in anything
that we looked at, we found there was no benefit for the drug over placebo.”

The study results may come as a surprise to psychiatrists and patients,
since guanfacine and a related drug, clonidine, have been used for years to
treat PTSD.

“They are commonly used, but what we hope now is that people shy away from
using clonidine and guanfacine,” Neylan said.

One expert said he was taken aback by the findings.

“I was so shocked that I had to think about it for two days. I was trying to
find a hole in the science and I can’t — this is a state-of-the-art
clinical trial,” said Dr. Randall Marshall, director of Trauma Studies and
Services at New York State Psychiatric Institute. “Their effect size was
zero — there’s no hint of a benefit.”

The study, which was funded by the U.S. Department of Veterans Affairs, is
published in the Dec. 1 issue of the American Journal of Psychiatry.

Guanfacine’s rise and apparent fall as a PTSD treatment may be an object
lesson in why randomized, controlled trials — such as the one Neylan’s
group conducted — are so important to assessing a drug’s worth, he said.

Guanfacine and clonidine are alpha-2 agonists, which means they bind to the
alpha-2 receptor on brain cells, blocking the release of a neurotransmitter
called norepinephrine, Neylan explained. Norepinephrine is the neural form
of the stress hormone adrenalin. Psychiatrists have long known that PTSD
patients have increased levels of norepinephrine activity in their brains.

“So, from the start, the whole idea was very appealing — you give a drug
like guanfacine that blocks the effects of norepinephrine, and you’d hope to
see some benefit,” he said. “It made intuitive sense. It was a lovely idea.”

In fact, it was such an attractive idea that more than 20 review articles
and guidelines, published in a variety of psychiatric journals, touted the
use of guanfacine and clonidine in easing PTSD symptoms.

But no one had ever put this idea to the test in a randomized, controlled
trial.

In its eight-week study, Neylan’s group compared the effects of guanfacine
and an identical-looking placebo pill in 63 male and female veterans
diagnosed with PTSD. Twenty-nine participants were randomly picked to take
guanfacine while the other 34 took the dummy pill.

By the end of the study, the researchers found no net difference between the
two groups in terms of changes in symptoms.

“But the one thing that did clearly come out was that there were more side
effects with guanfacine,” Neylan said. “There was more sedation, feeling
fatigued, dry mouth.”

Why did a pill that should have worked so well in theory fall flat in
practice? Neylan offered one possible answer. “[Too much] norepinephrine can
be a bad thing,” he noted, “but you also need it for your brain to work
well. So, lowering the whole pool of norepinephrine did not seem to be an
effective strategy.”

He said the relatively small sample size in the study means he can’t be
absolutely certain that alpha-2 agonists have no benefit, “but we did get a
zero effect size. That means that even if we had 5 or 6 times this sample,
the probability of showing a meaningful difference is really, really low.”

Marshall agreed that the methodology is sound, and the findings conclusive.
“I think this pretty much answers the question of whether, in this
population, guanfacine should be considered as either a primary or an
adjunctive treatment. The answer is no — it’s a big surprise,” he said.

The finding will change the way he and psychiatrists everywhere treat PTSD
patients, said Marshall, who is also associate director of the Anxiety
Disorders Clinic and an associate professor of clinical psychiatry at the
Columbia University College of Physicians and Surgeons. He believes that,
despite the anecdotal success of guanfacine in isolated cases, “We should
not generalize that to PTSD or treatment-refractory PTSD.”

Neylan said a newer drug that works on norepinephrine receptors, but in a
different way, might still succeed where guanfacine has failed.

That drug, called prazosin, blocks the alpha-1 receptor in the synapse.
“There have been a few trials to show that prazosin does have some promise,
and I know the VA is gearing up to do a large multi-site study. It is
becoming more popular.”

In the meantime, he said, it’s important to remember that the first-line
therapy for most people with PTSD is antidepressants and/or psychotherapy,
especially “exposure therapy,” where patients are gently confronted with
reminders of the traumatic event itself.

“Most people feel that PTSD benefits most from a combination of
pharmacologic treatment and psychotherapy,” Neylan said.

Moe information

To learn more about PTSD, head to the U.S. National Institute of Mental
Health .

(SOURCES: Thomas Neylan, M.D., medical director, PTSD treatment program, San
Francisco VA Medical Center, and associate professor, psychiatry, University
of California, San Francisco; Radnall Marshall, director, Trauma Studies and
Services, New York State Psychiatric Institute, New York City; Dec. 1, 2006,
American Journal of Psychiatry)