Pubdate: Tue, 29 Nov 2005
Source: New Scientist (UK)
Copyright: New Scientist, RBI Limited 2005
Contact:  http://www.newscientist.com/
Details: http://www.mapinc.org/media/294
Author: Will Knight
Bookmark: http://www.mapinc.org/meth.htm (Methamphetamine)

ANTI-SMOKING DRUG MAY CUT CRYSTAL METH CRAVING

A Popular Treatment for Nicotine Addiction Can Also Cut Cravings 
Among Crystal Meth Addicts, a US Study Suggests.

Crystal meth - the commonly used term for methamphetamine - is a cheap
and addictive drug that has become a massive problem in the US in
recent years. It increases alertness and creates sensations of
euphoria in users by stimulating the generation of dopamine and
norepinephrine - neurotransmitters within the regions of the brain
responsible for feelings of pleasure.

Bupropion - the active chemical ingredient found in the nicotine
addiction drug, Zyban, as well as the anti-depressant Wellbutrin - was
found to reduce the drug-induced high experienced by methamphetamine
users and also to lessen their urge to take the drug in response to
visual cues, in a study by researchers at the University of California
in Los Angeles (UCLA).

Twenty methamphetamine users were given either 150 milligrams of
bupropion twice a day for a week, or a placebo.

Subjects were then injected with 30 milligrams of methamphetamine and
asked to rate the high they experienced on a scale of 1 to 10, with 10
being the most intense imaginable. The users given doses of bupropion
reported experiencing a significantly reduced high of, on average, 3
out of 10, compared to 5 out of 10 prior to the treatment.

"What we found, which was unexpected, was that it significantly
reduced the euphoric effect," Thomas Newton at UCLA, who led the
study, told New Scientist.

Video footage Bupropion is thought to reduce cravings for nicotine by
preventing it from getting into receptive parts of the brain. However,
the researchers behind the UCLA study believe it may cut cravings for
crystal meth in a different way. The drug inhibits the uptake of
dopamine and norepinephrine by brain cells so they stay around longer.
This may lessen cravings for crystal meth by decreasing the withdrawal
effects normally experienced by users, when the neurotransmitters are
taken up by neurons.

Crystal meth users given bupropion also reported far less of a craving
in response to video footage of actors simulating drug use. Such
visual cues would normally be expected to trigger a strong impulse to
take the drug.

Newton admits there may be confounding factors involved. For example,
he says several of the subjects of the trial smoked, and that smoking
may act as a cue for methamphetamine use. So bupropion might have had
an indirect impact by reducing the subjects craving for nicotine.

The group has begun second stage trials and hopes to work out
precisely how bupropion may decrease craving among crystal meth users.
"These findings may point the way towards medications with even
greater potential to be helpful," Newton says.

Journal reference: Neuropsychopharmacology (advance online
publication)
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MAP posted-by: Richard Lake