The warning relating to the drug Chantix had been in place for seven years. This was due to post-marketing reports from patients. Chantix (generic name Varenicline) blocks the pleasure areas of the brain from responding to nicotine, thereby eliminating the “buzz” that smokers get from inhaling tobacco products (the drug is a nicotinic receptor partial agonist.)
The warning has been removed (though other warnings still exist) after a review of evidence by the European Medicines Agency. The Agency no longer thinks the drug has any association with dangerous psychiatric side effects.
This change in direction is based on a review of a study involving 8,144 patients, who took the drug, throughout 16 countries. This data indicated, statistically, that there was no increased risk of suicide or suicidal thoughts among the study participants. In the study users of the medication were examined alongside a control group who did not take the medication.
Pfizer conducted the study in response to what it felt was anecdotal evidence that the anti-smoking medication had any connection with suicidal tendencies. Such evidence, nonetheless, was sufficient, in 2009, for both the European regulator and the U.S. Food and Drug Administration (FDA) to impose a warning notice. Although a warning note was added, the drug was never banned.
The warning stated the medication could lead to “changes in behavior, hostility, agitation, depressed mood, and suicidal thoughts or actions.”
The FDA warning, for this and any other product that falls into the ‘potentially dangerous’ category, is denoted by a black box on the packaging of the products. A similar warning was issued to another anti-smoking product called Zyban, which is manufactured by GlaxoSmithKline. Zyban (generic name Bupropion) is an anti-depressant aimed to help heavy smokers cope with nicotine withdrawal (it acts as an norepinephrine-dopamine reuptake inhibitor.) No changes in Europe are on the table for Zyban.
Many doctors did not prescribe the product due to the warning in place. Meanwhile, the FDA is set to review its warning in light of the new study.