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Reports of Psychotic Violence on Anti-Smoking Drug Chantix Pile Up But Pfizer Isn't Seeing Them

Pfizer (PFE)'s anti-smoking drug Chantix (sold as Champix in some countries) is looking increasingly vulnerable to litigation or further limits to its marketing in light of a new study that looks at episodes of psychotic violence associated with the drug. Part of the problem is that in 2008, Pfizer chief medical officer Joseph Feczko said the company was continuing to study the drug. Two years later, studies and anecdotal evidence are continuing to turn up problems that go beyond suicidal thoughts generated in some patients. And yet researchers linked to Pfizer haven't published any significant psychological issues generated by the drug.

The FDA added a black box warning to Chantix in 2009, but that only covered suicidal harm not harm toward others. A study in The Annals of Pharmacotherapy covers just 26 cases of "inexplicable and unprovoked" violence linked to Chantix. It's anecdotal and thus not statistically significant, but it still makes disturbing reading:

A woman struck her 17-year-old daughter in the mouth while the daughter was driving a car, with a young granddaughter also present (case 19). A 42-year-old man punched a stranger at a bowling alley (case 3). The stranger and 2 friends responded and knocked out the subject's front teeth. A 24-year-old female started beating her boyfriend in bed because he "looked so peaceful" and she later attempted suicide (case 1). A 29-year-old female struck an acquaintance twice in the face, and then started smashing doors in her own home and beating on her truck (case 21). The actual or intended victims of aggression/violence were anyone who happened to be nearby.
Here's the results table (click to enlarge):

If you've ever talked to anyone who's taken Chantix, you'll hear some weird tales. Here's a great piece in New York magazine about the mind-altering qualities of the drug experienced by the author:

By night four, my dreams began to take on characteristics of a David Cronenberg movie. Every time I'd drift off, I'd dream that an invisible, malevolent entity was emanating from my air conditioner, which seemed to be rattling even more than usual. I'd nap for twenty minutes or so before bolting awake with an involuntary gasp. I had the uneasy sense that I wasn't alone.
... I'd dream that something increasingly ominous -- carbon monoxide? Vampires? -- was sucking vital essence out of me.
The most unsettling thing about sleeping on Chantix is that I never felt like I was truly asleep.
As I showered, shaved, and scrambled into clothes, I tried to shake a weird, paranoid sense that I'd just been psychically raped by a household appliance.
Violent feelings are probably more common than those collected by the FDA in the official statistics. Here, for instance, is a sample of more than 800 comments made by Chantix patients:
need2quitnow: I don't want to smoke but I feel awful! Lack of appetite, crazy dreams, feel depressed, antsy and angry.

staple003: It worked untill I stopped taking it. I had to stop taking it because of the side effect making me very impulsive and sometimes uncontrollable.

citygirl12: Chantix didn't work for me. I was crying everyday!!!! Not a good thing when you're trying to quit smoking. Good for some, not all.

clarko36401: It worked for about 3 months. I had some really messed-up side effects from the medicine. It could have been responsible for the flair-up of a deep depressive episode that lasted for a long time

STLBrian: Cutting cravings dramatically. Makes me feel weird and gives me very wacky dreams every night. Those are kind of fun though so I'm not complaining.

The drug has also been linked to the shooting death of the guitarist for Edie Brickell and the New Bohemians, two dozen Los Angeles traffic accidents, and it's been banned for use by airline pilots.

UPDATE: In a statement to BNET, Pfizer said it does monitor the drug for adverse events:

... All post-marketing reports of adverse events are reviewed by Pfizer, and reported to regulators, including FDA. The currently approved Chantix label contains a boxed warning regarding reports of serious neuropsychiatric events reported in some patients. If these neuropsychiatric symptoms are observed by the physician, patient or caregiver, patients should stop taking Chantix and notify their healthcare provider immediately. There is no reliable scientific evidence demonstrating that Chantix causes these events.

Clinical studies are underway to help us further characterize the benefit risk profile of CHANTIX in different smokers. The ongoing studies are registered on ClinicalTrials.gov and their results will be posted both on ClinicalTrials.gov and ClinicalStudyResults.org. Pfizer is also currently in discussions with the U.S. Food and Drug Administration (FDA) regarding the design of a large, prospective, randomized controlled clinical trial studying Chantix in smokers with and without mental health disorders who are attempting to quit. As studies complete, the results will be published.

In fact, an April 2010 study by Dr. Serena Tonstad (of the Ulleval University Hospital, Oslo, Norway) that looked at 10 Chantix trials found no significantly higher rates of psychological side effects compared to those on placebo. Perhaps unsurprisingly, Tonstad has received funds from Pfizer for three smoking trials and as a consultant.

Chantix sales rose 7 percent in Q1 2010 to $189 million. Plaintiffs' lawyers will be eyeing every penny of that.

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