Continuing controversy over the stop-smoking drug Chantix could hurt sales of the Pfizer Inc. product, the Associated Press reported May 22.

Goldman Sachs analyst James Kelly is predicting slacker sales for Chantix after the U.S. Federal Aviation Administration (FAA) banned use of the drug for pilots and air-traffic controllers, citing reports of serious side-effects in a study by the Institute for Safe Medication Practices.

Earlier, the U.S. Food and Drug Administration (FDA) said that it is "increasingly likely" that a link exists between Chantix and serious psychiatric problems.

Kelly said the bad publicity has contributed to a reported 20 percent decline in Chantix sales this year, and he has predicted reduced profits for Pfizer as a result. However, he said, "Chantix is an important growth driver for the company and may still contribute globally as patients and physicians weigh the long-term benefits of smoking cessation versus a short-term course of therapy."