A new research study published online ahead of print in the journal Annals of Pharmacotherapy concludes that the drug Chantix (varenicline) is most likely causally associated with thoughts and acts of aggression and violence (see: Moore TJ, Glenmullen J, Furberg CD. Thoughts and acts of aggression/violence toward others reported in association with varenicline. Annals of Pharmacotherapy 2010).
The authors identified 26 cases of FDA-reported adverse drug events associated with varenicline that included acts and thoughts of aggression and violence toward others and met the WHO criteria for possible, likely, or certain association with the drug. This excluded cases involving suicide if there was no violence toward others. In all 26 cases, there were inexplicable and unprovoked acts or thoughts of violence toward others. In 24 of these 26 cases, there was no indication of a prior history of violence. Perhaps most importantly, in 10 of 11 cases in which there was information about the effect of the discontinuation of varenicline, the symptoms resolved in a few days after the drug was discontinued.
The study concludes as follows: "These data contain several characteristics that add scientific weight to the accumulating evidence that varenicline is associated with unprovoked acts and thoughts of aggression/violence toward others. The temporal relationship evidence was strong, with an early and often immediate onset of abnormal dreams and thoughts, and the adverse effects usually resolved with discontinuation of treatment. In the 3 rechallenge cases, the adverse effects reappeared (often in more severe form) when the drug was restarted and disappeared when the drug was stopped again. The patient population of predominantly middle-aged women was typical of those who are trying to quit smoking with varenicline but is an unlikely age group and sex for assault and acts of violence toward others."
The Rest of the Story
It appears that after careful review of the adverse events associated with Chantix that were reported to the FDA, we now have about as strong the evidence that we could possibly have that Chantix is causally associated to sudden, inexplicable and unprovoked acts of aggression and violence toward others in the absence of any prior history of similar events.
Oddly, despite the fact that Chantix has been clearly associated with fatal adverse events, the major anti-smoking groups are not calling for its removal from the market. At the same time, the same groups are calling for another product that is being used for smoking cessation - electronic cigarettes - to be removed from the market even though there have apparently been zero adverse events reported to the FDA.
The logic here makes no sense to me. There are hundreds of reports of severe and even fatal adverse events from Chantix, a drug which fails to produce long-term smoking cessation nearly all the time that it is used (that is, about 88%) but anti-smoking groups want it to stay on the market. At the same time, these groups want to pull from the market electronic cigarettes, which anecdotally appear to be quite effective in achieving smoking cessation and which have no known or reported adverse effects.
Now don't misinterpret this post. I'm not necessarily calling on the removal of Chantix from the market. However, I do think that we should treat electronic cigarettes and Chantix in a manner that is consistent, logical, and sensible.
When a product on the market is benefiting many people and leading to marked health improvement, the burden of proof is on those who want it removed from the market to demonstrate that the product is causing harm. This is why we err on the side of leaving products on the market until they are shown to be harmful. Since electronic cigarettes are already on the market, I feel that the same standard should hold. They should be removed from the market only if it is demonstrated that they are causing adverse effects. The burden of proof is on those who want the product removed.
Thus far, no one has demonstrated that there are adverse effects from electronic cigarettes, nor has anyone so much as offered a plausible hypothesis for how electronic cigarettes could cause harm to users (i.e., pointed to a chemical or chemicals in the product that are known to be health hazards).
Removing electronic cigarettes from the market would, with certainty, cause harm to thousands of vapers. You don't knowingly cause harm to people simply because of the speculation that a product could have adverse effects. Yet that's precisely what the anti-smoking groups want the FDA to do.