Photo by 55Laney69, via Flickr
Photo by 55Laney69, via Flickr

Chantix, Suicide, and the Point of Prescription Drug Warnings

Quick poll: Think back to the last time you bought a prescription medication. Did you read any of the information about the drug printed on the papers inside the box? And if you did read it, did that stop you from taking the drug?

I can’t recall a time when I read any of that fine print, despite the fact that I’m fascinated by medicine and often write about it. I got thinking about the potency (or impotence) of these warnings this week while reading about a controversy surrounding Chantix, a drug that helps people quit smoking.

Chantix (Pfizer’s branded name for varenicline) works by stimulating nicotine receptors in the brain, thus curbing cravings for cigs. The Food and Drug Administration (FDA) approved the drug in 2006. Since then, a small percentage of people who take Chantix have reported neurological side effects, and serious ones: depression, psychosis, erratic behavior, even “feeling like a zombie.” The drug has been linked to more than 500 suicides, 1,800 attempted suicides, and the bizarre death of an American musician. Here are a few anecdotal reports about the drug from a Reddit thread:

  • Chantix was the most miserable drug I have ever taken…severe gi distress, depression, paranoia, crazy and vivid dreams, etc. BUT, it got me off cigarettes after everything else I tried had failed…As I knew that it really fucked with you I prepped by temporarily getting rid of the guns and having my brother check up on me daily…What keeps me from going back to smoking is knowing that one day I’ll want to quit again, and I NEVER want to experience Chantix again!!!
  • I’m convinced Chantix played a part in my divorce. My ex gave up smoking, her Pepsi habit, as well as marriage.
  • My mother was on it (and successfully quit smoking using it) and she had some outrageous paranoia. She would accuse us of conspiring against her, making her sick, not loving her, lying to her, stealing things (that she misplaced), turning the dog against her (da fuq??), trying to poison her and sabotaging her car…she smoked for 40 years and failed at quitting hundreds of times. Chantix did the trick somehow but made her nuts.

Yikes! Reading stories like that might scare me enough to think twice about the drug. But would the information in the package insert?

That insert has been the focus of the recent hoopla about Chantix. In 2009, the FDA decided that the Chantix insert needed a “black box warning” about the risk of neurological side effects (so named because this text is outlined with a black border). Here’s part of that warning:

Advise patients and caregivers that the patient should stop taking CHANTIX and contact a healthcare provider immediately if agitation, hostility, depressed mood, or changes in behavior or thinking that are not typical for the patient are observed, or if the patient develops suicidal ideation or suicidal behavior while taking CHANTIX or shortly after discontinuing CHANTIX.

The black box is the FDA’s most severe safety warning. Pfizer fought it tooth and nail, citing several studies showing that Chantix is not associated with a higher risk of psychiatric problems. (If you want to read more about these studies and counter arguments from the FDA advisory panel, check out this excellent piece by John Gever at MedPage Today.) Earlier this month, the FDA confirmed that the warning would stay, and in fact suggested that it have even stronger language.

But… why so much fuss over these warnings, anyway? Does anyone actually read them?

There doesn’t seem to be a lot of research on that question, though the data that does exist suggests that some patients are more conscientious than I am. One report I stumbled on, surveying 1,500 patients from a community pharmacy in Germany in 2001, found that 80 percent always read the inserts. A 2007 study looked at 200 patients in Israel who were prescribed antibiotics, analgesics or antihypertensives. It found that just over half of participants read the inserts. And a 2009 study in Denmark found that 79 percent of patients “always or often” read them. On the other hand, a 2006 report of American consumers reported that just 23 percent looked at this info.

Even if patients are interested in reading those materials, they might not understand the information. A 2011 study asked 52 adults with a high-school education or less to read the package insert and similar materials describing an antidepressant medication. Afterwards, less than 20 percent could name the the rare-but-dangerous side effect of the drug. A report from the Institute of Medicine similarly concluded that drug labeling is a big part of why patients often use drugs incorrectly.

Studies like those have led some researchers to propose ways to make labels more useful to patients. But the reason Pfizer was so concerned with the black box warning for Chantix has little to do with consumer behavior. The company was worried because of the warning’s potential influence on doctors and their prescribing habits.

There aren’t many studies looking closely at the correlations between black-box labeling and prescribing patterns. But there are two notable examples that seem to suggest that the warnings have teeth. Remember the Vioxx controversy? Vioxx was a hugely popular anti-inflammatory drug that was pulled from the market in 2004 because of its risk of heart disease and stroke. After that, the FDA reacted by issuing black-box warnings for several similar drugs, leading to a “rapid decline” in prescriptions.

The other example comes from the link between antidepressants and suicide in children and adolescents. In March 2004 an FDA advisory committee reported on this link, and several months later it issued a black-box warning on all antidepressants. By June 2005 prescriptions for children and adolescents had dropped 20 percent.

To sum up, I was wrong: prescription warning labels, though flawed, actually matter to many patients, doctors and pharmaceutical companies.

As for Chantix… if you’re thinking of trying the drug to quit smoking, you might want to wait until results come back from a prospective clinical trial slated to end next year.

UPDATE at 11:50am: I added the sentence about the 2006 report on Americans’ use of package inserts. (Thanks, Kelly Hills!)