Fluoxetine
(brand name Prozac )
How Prozac Works in Weight Loss
SSRIs like fluoxetine (Prozac),
sertraline (Zoloft),
and
Paroxetine (Paxil or Pexeva)
block the signaling neuron’s ability to take up the left over neurotransmitter called
serotonin.
This means the receiving neuron is exposed to the serotonin signal for
a longer amount of time. This excess serotonin is what makes people
feel better/happier and is why SSRIs are antidepressants. It is not
clear exactly how SSRIs, like Prozac, help in weight loss, but is is
believed that serotonin helps regulate your appetite. The more
serotonin in the synapse, the less hungry you should be.
Pros
Studies
have shown that these medicines help people lose weigh in the short
run. Many other antidepressants cause people to gain weight. Prozac,
Zoloft, and Paxil generally cause people to lose weight.
Because
these are antidepressants, these medicines may also help you to feel
better, especially if you have depression. However, the doses are
different, so you should discuss this with your doctor.
Cons
The
amount of weight loss to expect has a wide range. Some people who do
not have much of an appetite because they are depressed may begin
eating once they feel better and actually gain weight. After the first
six months of treatment, most people regain half of the weight they
lost within the next six months.
The
dose of Prozac for weight loss is three times higher than the dose
generally given for depression. A higher dose means that more of the
medicine has to be in your body. Therefore, there is more of a risk for
side effects. Most doctors’ experience is with the lower dose used for
depression.
These medicines carry a warning from the FDA that they may actually increase the risk of suicide.
Mania
and
serotonin syndrome
are also among some of their side effects.
Other Comments
In most studies, a diet was also given with the medicine and some included exercise. Diet and exercise should be continued with medicines only serving as a weight loss aid.
Most
of the studies on weight loss were done on fluoxetine. It is harder to
make a recommendation about using sertraline or paroxetine.
Return to Home Page or Weight Loss Drugs.
It
is important you discuss any weight loss or exercise plan with your
doctor. Only you and your physician can decide what is best for you.
Some people have certain conditions that prevent them from doing all
exercises, and goal body weights may be different for different people.
You need to discuss all these things with your physician before
starting any weight loss or exercise program.
This article was written by John Vickery, MD.
References
Ann Intern Med 2005;142:525-531
“Drug therapy of Obesity” UpToDate version 15.3
Treatment Guidelines from The Medical Letter 2003;1:101
The Medical Letter on Drugs and Therapeutics 1994;36:107-108
Epocrates Online @ http://www.epocrates.com accessed on 3/3/2008
