By Emily P. Walker,
Washington Correspondent, MedPage Today
Published: October 24, 2011
WASHINGTON — Smokers who take the smoking-cessation drug varenicline (Chantix) are no more likely to be hospitalized for psychiatric events than those who are using a nicotine patch to quit, according to data from two large government studies released Monday by the FDA.
However, that doesn’t mean that the quit-smoking drug might not be to blame for mood changes including hostility, agitation, depressed mood, and suicidal thoughts or actions that don’t end in hospitalization, the FDA cautioned in adrug safety communication posted to its website.
Varenicline works by blocking nicotine’s effect on the brain, and has been shown to help smokers avoid cigarettes for as long as a year compared with placebo.
Soon after the drug was approved in 2006, some patients taking varenicline reported changes in behavior soon after they started the drug, including depression and suicidal behaviors. The FDA confirmed dozens of suicides among people taking the varenicline, and hundreds of cases of mood changes.
Neither of the studies reported Monday — one of which was conducted by the Department of Veterans Affairs (VA) and the other by the Department of Defense (DoD) — found a difference in risk of neuropsychiatric hospitalizations between patients taking varenicline or using nicotine patches to help quit smoking.
The VA study was a retrospective cohort study of more than 14,000 varenicline users and the same number of patch users. Researchers compared the incidence of psychiatric hospitalization — for drug-induced mental disorders, schizophrenic disorders, other psychotic disorders, depression, suicide attempts, and other mood disorders — among the two groups, and found no difference at 30 days after starting treatment.
The DoD study also was a retrospective cohort study comparing rates of hospitalizations for neuropsychiatric adverse events among nearly 20,00 varenicline users and nearly 16,000 patch users who were active military personnel, military retirees and dependents. Again, there was no statistically significant difference in neuropsychiatric events between those who used varenicline to quit smoking and those who used a nicotine patch.
However, both studies had a number of design flaws, the FDA said, including testing only for neuropsychiatric events that resulted in a patient being hospitalized.
“Focusing on psychiatric hospitalizations is a useful approach for assessing the risk of serious neuropsychiatric adverse events, but it does not allow an assessment of less severe neuropsychiatric events that did not result in a psychiatric hospitalization…” the FDA wrote.
The FDA said the studies didn’t rule out an increased risk for other neuropsychiatric events, including those that don’t end in hospitalizations.
A 2009 study found that people with a history of depression were no more likely than others to report new or worsening depressive symptoms when they took varenicline.
Varenicline will keep its black box warning alerting patients and doctors to be aware of changes in behavior, hostility, agitation, depressed mood, and suicidal thoughts or actions in patients taking varenicline.
Even with that warning, the benefits of varenicline continue to outweigh the risks, the FDA said.
Pfizer is performing a larger study on the drug’s neuropsychiatric risks, and those results are expected in 2017.
Aside from potential risks to the brain, there also has been concern about how varenicline affects the heart.
In June, the FDA updated varenicline’s label to warn that smokers with a history of heart attack or stroke who use varenicline may increase their risk of a second heart attack or new onset peripheral vascular disease. The following month, the FDA warned about the potential for a small, increased risk of certain cardiovascular adverse events in patients with cardiovascular disease or chronic obstructive pulmonary disease (COPD).
Nearly 9 million people have received a prescription for varenicline, which does not contain nicotine, to help stop smoking in the past five years, according to the FDA.
Read the article online here.