Wednesday, November 21, 2007

FDA Investigates Chantix Link to Suicidal Thoughts, Aggressive Behavior, and Drowsiness

The FDA is looking into possible links between Pfizer's anti-smoking drug Chantix and various mental or emotional effects.  In its announcement yesterday -- Early Communication About an Ongoing Safety Review: Varenicline (marketed as Chantix) -- the agency summarized the reports it has received about side effects of Chantix.  The FDA is working with Pfizer "to further evaluate the potential association between Chantix and suicidal thoughts, aggressive and erratic behavior, and impairment that affects one’s ability to drive or operate machinery," and will report its conclusions and recommendations as soon as it completes its analysis.  In the meantime, "The FDA urges both healthcare professionals and patients to report side effects from the use of Chantix to the FDA's MedWatch Adverse Event Reporting program."

Here's an excerpt from today's Wall Street Journal article:

The Food and Drug Administration has received reports of "suicidal thoughts and aggressive and erratic behavior" in people taking Chantix, the smoking-cessation drug sold by Pfizer Inc., but it is too soon to say whether the drug is clearly linked with such problems, the agency said yesterday.

Pfizer said yesterday that it had updated the drug's label to include "reports of depressed mood, agitation, changes in behavior, suicidal ideation, and suicide in patients attempting to quit smoking while taking Chantix."

... The agency said it is reviewing reports of drowsiness in some people taking the drug, and it recommended that patients taking Chantix be careful driving and operating machinery until they know how the drug affects them. Patients should tell their doctors if they have mood or behavior changes while taking the drug.

Pfizer denies proof of causation.  The WSJ article quotes a Pfizer medical director who emphasized that quitting smoking can cause nicotine-withdrawal symptoms regardless of whether an anti-smoking drug is used.  At Pharmalot, Ed Silverman wrote about this yesterday in Up in Smoke?  Pfizer's Chantix and Suicidal Thoughts, and reports Pfizer's reaction:

A Pfizer spokesman e-mailed us to say that Chantix labeling has been updated to reflect the various reports, but emphasized that “there is no scientific evidence establishing a causal relationship between Chantix and these reported events…In clinical trials involving more than 5,000 patients, adverse events related to changes in behavior or psychiatric symptoms, including suicidal ideation, were rare and occurred at a rate comparable to placebo-treated patients. There were no suicides in patients taking Chantix in our clinical trials.”

A post on Chantix on the Mass Tort Litigation Blog one year ago has generated 100 comments, mostly by Chantix users discussing side effects they have experienced.  To our surprise as blog editors, the comments page to that post has become something of a chat room for worried Chantix users.  Is this the first stages of the sort of mass tort networking about which Byron Stier has written?

I understand that neither Chantix users nor Pfizer looks at this from an academic perspective.  I also understand that, for them, this is not (or at least, one hopes, not primarily) about tort liability and litigation.  For users, this is about personal health, and for Pfizer, it's about both corporate responsibility and a product that is critical to the company's revenue. 

But for those of us who try to understand the development of mass tort litigation, it's fascinating to watch the seeds of potential litigation at a point when we know that some litigation is inevitable but do not know whether the lawsuits will flourish and replicate.  Four million U.S. patients took Chantix.  There are plaintiffs' attorneys advertising for Chantix clients.  But it's very early.  Beck and Herrmann, in their Anatomy of a Mass Tort (which I think was right on target), described how mass torts begin:

A mass tort does need a trigger. We'll bet the mortgage that one of these five events started the avalanche: (1) bad press -- Connie Chung or Mike Wallace said something nasty, (2) regulatory action -- the FDA added a black box warning to a drug or the National Highway Traffic Safety Administration recalled a car, (3) a voluntary recall -- although no government agency demanded it, a manufacturer took its product off the market, (4) a big jury verdict -- nothing catches the eye of the plaintiff's' bar like money, or (5) a critical article in the scientific literature -- historically, we didn't see this trigger too often, but it's becoming increasingly common.

Even as we watch a potential endgame in Vioxx with Merck's settlement offer, and follow asbestos litigation in its over-mature stage, it's interesting to look at yesterday's FDA announcement when we don't yet know whether that announcement will turn out to be a mass tort trigger, and to look at the informal networks developing among Chantix users when we don't yet know whether the chat room will become a litigation plaintiff network.


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"There were no suicides in patients taking Chantix in our clinical trials.”

This is actually untrue. Ed posted an update on that.

Posted by: Mike | Nov 21, 2007 9:28:04 AM

I have had problems since I started to take Chantix. In no way was I aware of the risks. Serious edema and mental health issues. I think that the drug is dangerous.

Posted by: Paula | Jun 27, 2008 3:04:09 PM

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