A new study has found that bupropion (Zyban), an
antidepressant, increases the odds of success for people who
are trying to stop smoking. The U.S. Food and Drug
Administration recently approved the use of bupropion as an
aid in smoking cessation.
The report was published in the Oct. 23, 1997, issue of the
New England Journal of Medicine. The 615 participants who
began the study were divided into four groups: One group
received a placebo while the other groups received daily
bupropion doses of either 100, 150, or 300 milligrams (mg) for
7 weeks. All participants received similar, brief stop-smoking
counseling several times during the treatment phase. Reports
of abstinence were confirmed by checking carbon monoxide
levels in the participants' breath.
At the end of the 7-week treatment period, 19 percent of
those taking placebos were abstinent from smoking. The
abstinence rate for the 300-mg group was 44.2 percent, the
150-mg group attained 38.6 percent abstinence, and the 100-mg
group had 28.8 percent abstinence. By the end of the year, the
abstinence rates were 12.4 percent for the placebo group, 23.1
percent for the 300-mg group, 22.9 percent for the 150-mg
group and 19.6 percent for the 100-mg group.
The study was conducted by researchers at three
institutions: Mayo Clinic, Rochester, Minn.; Palo Alto Center
for Pulmonary Disease Prevention, California, and West
Virginia University, Morgantown.
Mayo Health Oasis interviewed Richard D. Hurt, M.D., lead
author of the study and director of Mayo Clinic's Nicotine
Dependence Center, to discuss the results.
Oasis: Overall, what does the study tell you about
bupropion as a smoking-cessation medication?
Dr. Hurt: Bupropion is the first non-nicotine product that
works, but it is not a magic bullet. Smokers who are
interested in stopping smoking have a better chance with
bupropion than with a placebo. We also found that the higher
doses work better than the lower dose, and that the higher
dose decreases the weight gain that often occurs when a smoker
stops smoking.
Oasis: Why is an antidepressant of interest to
smoking-cessation researchers?
Dr. Hurt: Smokers are more likely to have a history of
major depression than nonsmokers, and nicotine may act as an
antidepressant in some smokers. The development of depression
after a person stops smoking may lead to smoking relapse, so
it was theorized that an antidepressant may help counteract
the loss of nicotine's effects. Of the antidepressants studied
so far, bupropion is the first shown to have efficacy in
smoking cessation.
Oasis: The abstinence rates among the 150- and 300-mg
groups were quite high at the end of the 7-week treatment
period, but had dropped by the end of the year. Would
treatment with bupropion for longer than 7 weeks help maintain
the higher abstinence rate?
Dr. Hurt: The abstinence rate at the end of the year was
still significantly higher for the 150- and 300-mg groups than
for the placebo and 100-mg groups, even though it had dropped
from the 7-week levels. The first step was finding out if
bupropion works, and we found that it does. It seems likely
that a longer treatment period might help some people, thus
the labeling of the drug for smoking cessation recommends a
treatment period of 6 to 12 weeks. Antidepressants are
commonly used for longer periods to treat depression. They
have almost no abuse potential. But we weren't looking at
long-term use in this study on smoking cessation. We wanted to
see if it worked at all. This study evaluated a short
treatment period similar to those used for nicotine-patch
studies.
Oasis: How do your results compare to nicotine-patch
studies?
Dr. Hurt: Favorably. The success rates at the end of
treatment and at 1 year are similar.
Oasis: Were there any surprises in your findings?
Dr. Hurt: Yes, besides finding out that bupropion works for
smoking cessation, we discovered that at the higher dose, 300
mg, there was less weight gain than at the other doses or with
the placebo for those who stopped smoking.
Oasis: So bupropion seems to help people stop smoking and
also gain less weight?
Dr. Hurt: Yes. That's an important factor in smoking
cessation. People who stop smoking typically gain weight —
usually about 5 pounds. The fear of gaining weight keeps some
people, particularly women, from even trying to quit. So a
medication that can help you stop smoking and also decrease
weight gain would offer an advantage.
Oasis: Were there any significant side effects or safety
concerns?
Dr. Hurt: Side effects were fairly minimal. The most
frequent were insomnia and dry mouth. Antidepressants in
general are associated with a small risk of seizure. We used a
newer, sustained-release form of bupropion that can be taken
twice a day instead of three or four times. It's also thought
to have a lower likelihood of causing seizures because it
doesn't have the high peaks and troughs that a more
immediate-release form does.
Oasis: Did anyone in your study have a seizure?
Dr. Hurt: No one had a seizure. However, we excluded from
the study anyone who had a personal or family history of
seizure, a history of severe head trauma, eating disorders, or
active alcoholism. Doctors should screen for the possibility
of seizures before starting treatment with bupropion.
Oasis: Did bupropion affect nicotine withdrawal symptoms?
Dr. Hurt: We didn't see any difference across the groups in
frequency or severity of withdrawal symptoms.
