Pfizer suggested that since nicotine withdrawal alone can cause mood swings and agitation, it may be impossible to determine if Chantix aggravates those behaviors.
But FDA said it found evidence of Chantix patients who experienced psychiatric problems even though they were still smoking.
"There are a number of compelling cases that look like they are the result of exposure to the drug itself and not other causes," said Bob Rappaport, a director at FDA's drug evaluation center. Some patients experienced the same psychiatric problems after they stopped using Chantix, he said, suggesting a negative reaction to withdrawal.
I know a few people who have taken it and a about half have complained of nausea if taken without food.
The other PINK meat!