Chantix Study Eases, but Does Not Eliminate, Concern

Bristol, UKChantix, once the darling of smoking-cessation aids, quickly moved under a black cloud of controversy as news emerged about Chantix suicide, Chantix aggression and other serious side effects. In July the US Food and Drug Administration (FDA) issued a black box warning for "serious neuropsychiatric symptoms," including changes in behavior, hostility, agitation, depressed mood, suicidal thoughts and behavior and attempted suicide.

However, a recent British study found that the data is inconclusive. Chantix (marketed as Champix in the UK) may well be no worse than any other smoking cessation aid, compromised as they all are by the challenge of overcoming nicotine cravings in the first place.

Writing on October 1 in the British Medical Journal (BMJ), researchers at the University of Bristol noted that the jury is still out on Chantix / Champix, adding that more data is needed to conclusively determine whether or not varenicline (Chantix) is unique in causing the side effects it has become notorious for. "Our study does not rule out the link between varenicline and suicidal behavior; more studies are required, but it does provide some reassurance," said the lead researcher David Gunnell in an e-mail interview with the Globe and Mail in Canada.

In the new study, British researchers analyzed database information on 80,660 men and women, ages 18 to 95, who were prescribed a smoking cessation product between September 2006 and May 2008. All were prescribed either varenicline, the antidepressant bupropion (Zyban), or nicotine replacement products like patches, inhalers, gum, tablets or lozenges. Researchers followed them throughout the duration of the prescription and for three months after the date of their last prescription.

There was no clear evidence that varenicline or bupropion increased the risk for self-harm, suicidal thoughts or depression, the study reported. However, the researchers added that "the limited power of the study means we cannot rule out either a halving or a twofold increased risk."

Critics of the study note that the call for an even larger study suggests that the issue cannot be put to rest so easily.

Health officials in Canada, the US and the UK have been inundated with reports of psychiatric problems from varenicline users, ranging from disturbing dreams, hostility, and aggression to suicidal thoughts and depression.

The FDA continues to monitor Chantix.

It should be noted that the British study was independently funded, without financial involvement from any pharmaceutical interest.