Antidepressants
and new drugs increase the odds of stopping smoking
The new anti-smoking drug varenicline was first licensed for use in the UK on
5th December 2006. An early Cochrane Review' of its effectiveness shows that it
can give a three-fold increase in the odds of a person quitting smoking.
Varenicline is the first new anti-smoking drug in the last ten years, and only
the third, after NRT and bupropion, to be licensed in the USA for smoking
cessation.
People become addicted to smoking tobacco partly because nicotine in the
smoke stimulates receptors in the nervous system that cause a release of the
feel-good hormone dopamine. Varenicline partially stimulates these nicotine
receptors and enables a low-level release of dopamine, which reduces withdrawal
symptoms. It also partially blocks nicotine from being absorbed by the
receptors, making continued smoking less satisfying. This reduces a person’s
need to smoke, and may help them to quit completely.
This conclusion was drawn by a group of Cochrane researchers after they
studied data from six trials that compared the effects of giving people either
varenicline or a placebo. Together the trials involved 2451 people on
varenicline and 2473 people on placebos.
Pooling the data showed that people taking varenicline increased their odds
of quitting approximately three-fold for 12 months or longer compared with those
on placebo drugs .
Data from some of the trials also showed that people given varenicline
increased their odds of quitting more than 1½-fold compared with those given
bupropion, an antidepressant drug that roughly doubles a person’s chance of
stopping smoking (see: next press release.)
"What we need now are some trials that make direct comparisons between
varenicline and nicotine replacement therapy" says Lead Review Author Kate
Cahill, who works in the Department of Primary Health Care at Oxford University.
New evidence boosts the conclusion that some antidepressants can double a
smoker’s chance of quitting
The most recent Cochrane Review² concluded antidepressants bupropion (Zyban)
and nortriptyline double a person’s chances of giving up smoking and have few
side-effects, but selective serotonin reuptake inhibitors (SSRIs) such as
fluoxetine (Prozac) are not effective.
Although nicotine medications are known to help people quit smoking, not
everyone is helped by them or wants to use them. One possible alternative is to
use antidepressants. The rationale for this is that some people may smoke to
combat depression and that stopping smoking could trigger depressive symptoms in
some smokers.
A Cochrane review first published in 1997 (and last updated in 2004) showed
that the antidepressants bupropion and nortriptyline increase a person’s
chances of giving up smoking, but selective serotonin reuptake inhibitors such
as fluoxetine (Prozac) do not. An updated version of the review published in Jan
2007 now adds 17 more trials to the dataset, and now shows that bupropion and
nortriptyline double a person’s chance of quitting - again SSRIs have no
effect.
"Since bupropion and nortriptyline appear to work as well in
non-depressed as depressed persons, this suggests they help smokers quit in some
way other than as antidepressants," says John Hughes, a Professor in the
Department of Psychiatry at the University of Vermont, Burlington, USA.
More information:
 Contact:
Amy Molnar amolnar@wiley.com
John Wiley & Sons, Inc.
South African
Cochrane Centre
The South African Cochrane Centre (SACC) offers a limited number of free
access registrations to The Cochrane Library to African residents. To apply for
a sponsorship please register here.
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