Study: Chantix Has Little or No Suicide Risk
Researchers Find No Clear Evidence of Self-Harm Risk From Antismoking Drug
Oct. 1, 2009 -- The antismoking drug Chantix has been linked to suicide and
suicidal thoughts, but a new study shows that if such a risk exists it is
likely to be very small.
Researchers from the U.K.'s drug regulatory agency and the University of
Bristol compared the incidence of suicide and self-harm among smokers taking
Chantix to that of smokers using the drug Zyban or nicotine-replacement
products to help them give up cigarettes.
Last July, the FDA announced it would require labeling for Chantix and
Zyban to include its strongest safety message, warning that people taking the
drugs should be closely watched for signs of suicidal thoughts, hostility, and
depressed mood in users.
At a news briefing, an FDA official said 98 suicides and 188 suicide
attempts had been reported among people taking Chantix since the drug was
approved for sale in the U.S. in 2006.
Fourteen suicides and 17 suicide attempts had been reported in users of
Zyban, which contains the same active ingredient as the antidepressant
Using data from a medical registry with roughly 3.6 million people living in
the U.K., epidemiologist David Gunnell, PhD, and colleagues identified 80,660
adults who were prescribed smoking-cessation products between September 2006
and May 2008.
About three-quarters of the prescriptions were for nicotine-replacement
therapies, including patches, inhalers, gum, tablets, or lozenges. Slightly
fewer than 11,000 prescriptions were for Chantix and around 6,400 were for
Using electronic medical records, the researchers searched for evidence of
fatal and non-fatal self-harm, suicidal thoughts, and depression over the
period in which the treatments were used up until three months after the last
prescription was filled.
After controlling for known risk factors for self-harm and depression, the
researchers found no clear evidence of an increased risk of self-harm, suicidal
thoughts, or depression in Chantix users or users of any of the other
"This is the first study to look at this question in detail, and the
results are largely reassuring," Gunnell tells WebMD. "Our best estimate is
that if there is an increase in the risk for fatal and non-fatal self-harm
associated with [Chantix] the risk is likely to be very small."
Gunnell says larger studies are needed to further quantify the risk. "Any
such risk has to be balanced against the risks associated with continuing to
The study was paid for by the U.K.'s drug regulatory group, the Medicines
and Healthcare Products Regulatory Agency (MHRA).
It was published today in the journal BMJ Online First.
In a statement issued Thursday afternoon, a spokeswoman for Pfizer Inc.,
which markets Chantix in the U.S., told WebMD the company considers the overall
risk-benefit profile of the drug to be 'favorable."
"Given the significant public health risks of smoking, Chantix is an
important treatment option for adults who want to quit smoking," Pfizer's Sally
She added that the company is conducting clinical trials of the drug in
patients with psychiatric disorders as well as other patient populations.