Nicotine,
Tobacco, and
Tourette Syndrome
Let
us start out with this note: We are not advising people to take up
smoking for their health or to cure Tourette Syndrome.
It
has been known since the early 1980's that nicotine - a natural product
derived from the tobacco plant - plays an important role in the brain.
Researchers think that nicotine acts by stimulating the chemicals
which play a fundamental role in transmitting messages between nerves
and across brain neurochemicals.
Whether
from a puff on a cigarette, chewing nicotine gum, or a nicotine patch
stuck to the skin, nicotine shifts the body into high gear as the
drug enters the bloodstream. Scientists generally attribute nicotine's
power solely to the activity it sparks in the brain. The stimulation
can make users feel good, even euphoric. It's also what makes them
crave more. Physicians, however, generally finger tobacco's thousands
of other chemical constituents, including known carcinogens - not
nicotine - for smoking tobacco cigarettes' nastiest side effects.
Therefore researchers caution that smoking is a bad way to get medical
nicotine for any reason including Tourette Syndrome.
The
properties that make nicotine a health hazard might also make it a
useful therapy for more than smoking cessation. "Nicotine is
a drug—not a poison or carcinogen—but a drug," says
Sergei A. Grando of the University of California, Davis. "Nicotine
is often a bad guy," he adds, "but it can also be a good
guy."
The
challenge in any of nicotine's possible uses is to identify people
for whom the drug's benefits outweigh its risks and to develop targeted
delivery methods, says Phillip A. Dennis of the National Cancer Institute
in Bethesda, Md.
Nicotine
and Tourette Syndrome Trial
In
Tourette Syndrome nicotine is thought to work by regulating the brain's
levels of message-carrying chemicals, such as dopamine and acetylcholine.
Tourette Syndrome patients may have excessive levels of dopamine in
the brain and are treated with drugs that block dopamine. Therefore
regulating the brain's use of dopamine may reduce some of the Tourette
symptoms - but not everyone responds to every medication used.
The
researchers are not entirely sure how it works, but suggest that by
latching onto a "nicotine receptor" on brain cells, it stops
the receptor playing its role in the mechanism of Tourette's instead.
So
having shown experimentally how a small dose of nicotine can greatly
increase the effect of a dopamine blocker in animals, Dr. Paul R.
Sanberg of the University of South Florida wanted to add nicotine
to the treatment of the Tourette Syndrome patients.
Professor Sanberg discussed his research at a conference of
the American Association for the Advancement of Science in Washington
February 21, 2000.
In
the eight-week study, Sanberg's team randomly assigned 70 young Tourette's
patients to either nicotine patches or placebo patches.
The
nicotine patch - also called the nicotine transdermal system is like
a bandage applied to the skin and may cause a mild itching or burning
sensation in the skin. This usually disappears within 60 minutes.
If a skin rash, redness or swelling appears, a doctor should be consulted.
The nicotine patch can cause excessive irritation to those with allergies
or other skin problems.
On
average, the patients on the nicotine patches were able to cut their
dosage of Haldol, a potent tranquilizer used to treat Tourette's with
a number of undesirable side effects, by about half, Sanberg says.
Dr
Archie Silver, who was involved with the research, said: "Not
only was the patch effective, but a much smaller dose of the medication
Haldol could be given. "That's especially important when treating
children or adolescents."
Initially they used nicotine gum - and within half-an-hour, many of
their tics had stopped. The patients were able to focus better, and
the children's parents reported that they do their homework and write
better. The vocal tics - blurting out vulgar words - were also reduced.
They saw quite a few benefits which lasted a few hours.
The greatest problem, however, was getting children to use the nicotine
gum properly as they hated it. "Nicotine gum tastes very bitter"
says Professor Sanberg " so instead of doing what they were supposed
to do, which is bite it and park it in their cheek where the nicotine
could be absorbed, they would chew it like bubblegum, swallow the
stuff and then get gastro-effects like wanting to throw up. It was
terrible."
Side-effects
Unfortunately,
some children did suffer increased side-effects, such as nausea and
dizziness. Nausea, a slightly increased heart rate, and itchiness
from the patch were the main side effects.
The
researchers said that there was no evidence that the children became
dependent on nicotine. It might help that the patches release
nicotine slowly so that it reaches its peak in the blood in about
three hours, much slower than when smoking a cigarette.
They
also note that patches may only be suitable for those whose symptoms
cannot be controlled any other way.
More
research is needed before nicotine patches become routine to treat
diseases. However, Sanberg said that if Tourette's patients cannot
control their symptoms with standard drugs, a low-dose patch might
be worth trying.
Also
Sanberg notes, "I think that nobody is saying per se that nicotine
is the right answer for these disorders - but the studies show that
if it does work, there are a number of drug companies out there who
have nicotine programmes. That´s to say they're designing new
novel drugs that are similar to nicotine, that will act at the nicotine
system in the brain, and maybe have more specific and fewer side-effects.
So they could be beneficial in these other diseases."
“Now
that we understand more about how nicotine works in the brain, we're
looking for nicotine substitutes that could more precisely target
specific brain disorders and have fewer side-effects than the patches."
Since
no drug firms have exclusive rights to nicotine, researchers say companies
have little interest in paying for studies to prove its health benefits.
However, several are working on nicotine substitutes that can be patented.
These drugs could be more precisely targeted against specific disorders,
carry fewer side effects, and be available as pills rather than patches.
Dr.
Sanberg said, another study reported in the Journal of the American
Academy of Child and Adolescent Psychiatry, found that the drug mecamylamine
(Inversine) appeared to be safe for children and to help those who
experience mood disorders such as depression, aggression or anxiety
along with Tourette's syndrome. Further research is needed to determine
if mecamylamine can also boost Haldol's effectiveness in reducing
motor tics in the same way that nicotine does. The mecamylamine study
was funded by Layton Bioscience Inc.
Nicotine Antagonist Relieves Depression In Children With Tourette's
Tampa,
FL (Dec. 10, 2002) -- A well-tolerated drug mecamylamine that blocks
nicotine receptors in the brain appears to relieve depression and
mood instability in children and adolescents with Tourette's syndrome,
a preliminary study by University of South Florida College of Medicine
researchers has found.
Brain's
Nicotine Receptors Also Target For Anti-depressants
New Haven, Conn. -- The same receptors in the brain that are activated
when a person smokes cigarettes also play a critical role in the effectiveness
of antidepressants, according to a study by Yale researchers in the
November issue of Biological Psychiatry.
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