The drug Chantix has been linked to increased risk of suicide, but new U.S. government stop-smoking guidelines for doctors nonetheless endorse the drug, the Associated Press reported May 8.

The guidelines from the U.S. Public Health Service said that while Chantix has been linked to depression and suicidal behavior, the Pfizer product remains the most effective drug for helping people quit smoking. The guidelines recommend stop-smoking counseling, but advise doctors to discuss medication with all patients who smoke. Doctors also are advised to inquire about patients' past psychiatric history before prescribing Chantix, and to monitor the mood and behavior of those on the drug.

The lead author of the guidelines, Michael Fiore, was a consultant to Pfizer as recently as 2005. The advisory panel that issued the guidelines reviewed 83 studies and found that Chantix was effective in helping about one in three smokers quit, whereas the six-month quit rate for patients receiving placebos was 14 percent.