July 1, 2009 -- The FDA warns that bizarre behavior -- including suicide -- is seen in people
taking the stop-smoking drugs Chantix and Zyban.
Both drugs now will carry "black box" labels warning that people taking the
drugs should be closely watched for signs of suicidal thoughts, depression, hostility, or other
changes in behavior.
"We want people to use these drugs carefully and pay attention," Robert J.
Temple, MD, director of the FDA's office of medical policy, said at a news
conference. "Stopping smoking is a goal we all want to work toward. We don't
want to scare people off these drugs -- we just want them carefully
It's not at all clear that the drugs actually cause these behavior changes.
Smokers are addicted to nicotine -- and when they quit, their withdrawal
symptoms can include many bizarre behaviors, including suicide.
However, Curt Rosebraugh, MD, MPH, director of one of the FDA's drug
evaluation units, said that some of the suicide reports came from Chantix users
who were still smoking.
Zyban's active ingredient is bupropion, the antidepressant medication sold
as Wellbutrin. While Wellbutrin
and other antidepressants have labels warning of suicidal thoughts, the warning
had not been fully extended to people taking Zyban to quit smoking.
"Our attention was focused on Chantix. It wasn't until we started looking
through things that we realized Zyban may have the same issues," Rosebraugh
said at the news conference.
The most disturbing reports to the FDA involve suicide:
98 completed suicides in Chantix users
14 completed suicides in Zyban users
188 attempted suicides in Chantix users
17 attempted suicides in Zyban users
These reports have not been fully investigated. There may be duplicate
reports, and the reports have not been definitively shown to be drug side
Rosebraugh said the smaller number of reports for Zyban does not necessarily
mean the drug is safer than Chantix. Many more patients take Chantix -- and
earlier reports of a suicide link spurred increase reporting of events possibly
linked to use of the drug.
Pfizer, the drug giant that makes Chantix, says the drug remains an
important tool for people who want to quit smoking.
"The purpose of the new boxed warning is to raise particular issue of
concern to physicians so they can mitigate it, by being more vigilant and
monitor patients more actively," Steve Romano, MD, Pfizer vice president and
head of medical affairs, said at a news conference.
The FDA will require Pfizer and Zyban maker GlaxoSmithKline to conduct
clinical trials to evaluate whether the companies' drugs actually cause
suicidality and behavior change. Unlike the clinical trials upon which drug
approval was based, the new studies will enroll smokers with underlying
Romano noted that Pfizer already is conducting a clinical trial to assess
Chantix's safety and effectiveness in people suffering from schizophrenia.
Suicide, and suicidal thoughts, have been linked to a wide variety of drugs,
including antidepressants, antibiotics, acne
drugs, and epilepsy drugs. However,
Rosebraugh said there have been no suicide reports linked to the use of
nicotine patches for smoking cessation.
GlaxoSmithKline did not respond to WebMD's request for comment and had not
issued a news release by publication time.