The smoking cessation drugs Chantix (varenicline) and Zyban (bupropion) do not increase the risk of suicide or depression, compared with nicotine replacement therapy, a new study concludes. The U.S. Food and Drug Administration (FDA) has issued safety warnings about using these drugs to help people quit smoking.

“Given the concerns and accompanying safety warnings for these drugs, these findings are reassuring for users and prescribers of smoking cessation medicines,” study co-lead author Dr. Kyla Thomas of the University of Bristol said in a news release.

The study, published in BMJ, included data from more than 119,000 British adults who used various products to help them quit smoking. About 26 percent used Chantix, 6 percent used Zyban and more than two-thirds used nicotine replacement therapies, such as gum or patches.

The study did not find an increased risk of suicidal behavior or depression among those who used Chantix or Zyban, according to HealthDay.

In October 2011, the FDA determined Chantix is no more likely than nicotine patches to cause psychiatric events that require hospitalization. The FDA drew its conclusions after reviewing two studies comparing Chantix to nicotine replacement therapy, including nicotine patches. The agency acknowledged the studies had limitations and decided to keep the “black box” warning labels on Chantix to advise about possible psychiatric side effects, including changes in behavior, hostility, agitation, depressed mood and suicidal thoughts or actions.

The FDA also noted in 2011 that Chantix may be associated with a small, increased risk of certain heart problems in patients with heart disease. The risk information was added to the “Warnings and Precautions” section of the Chantix physician labeling, and was included in the patient medication guide.