Study Links Chantix to Violence and Aggression

Portland, ORFor patients looking to quit smoking, Chantix might seem like the perfect aid. Unfortunately for some, Chantix side effects are far more harmful than smoking. A new study suggests a link between the use of the smoking cessation drug and increased violence and aggression.

The study, "Thoughts and Acts of Aggression/Violence Toward Others Reported in Association with Varenicline [the generic version of Chantix]," was published in the Annals of Pharmacotherapy (online, 07/20/10). Researchers Thomas J. Moore, Joseph Glenmullen and Curt D. Furberg set out to identify whether or not patients who used varenicline treatment had common characteristics in their thoughts or acts of violence or aggression. They then examined whether or not those behaviors could be linked to the use of varenicline.

To carry out their study, researchers used adverse event reports from the US Food and Drug Administration (FDA), cases from clinical trials and cases from published literature. Among the events they examined were 10 events that involved assault, nine cases of homicidal ideation and seven cases of other thoughts or acts that could be classified as aggression and/or violence.

Researchers found that there were four main common characteristics in these violent or aggressive acts: the act was unprovoked, the victim could be any person nearby, there was no indication that the patient had previous similar behavior, and there were early signs of "psychiatric adverse effects." Those psychiatric adverse events started, in some cases, soon after the first dose of Chantix and included nightmares and sleep disturbances.

The information led researchers to conclude that their study "strengthens the accumulating scientific evidence that varenicline is associated with thoughts and acts of aggression/violence." They went on to recommend that patients be fully informed about the risk of violence and aggression, and that patients contact a healthcare provider if they experience any of those symptoms.

The good news was that in cases where follow-up information was available, the psychiatric adverse effects resolved after the medication was stopped in 93 percent of cases.

The study did not include information about situations in which the violence or harm was directed at the patient—such as suicide attempts—unless those situations also involved aggression or harm to other people. Therefore, the study does not comment on the link between Chantix and suicide or suicidal ideation. Researchers noted, however, that three of the cases they studied ended in suicide and that four others attempted suicide.