I'd say it would depend on the amount of alcohol you drank, but some of the ingredients may have reacted with the alcohol.
Here's a tidbit I found that you might be interested in:
http://www.drugstore.com/ask/are-there-any-drug-interactions-with-xenadrine/qxa1740
It says "there's no medical research to support claims that Xenadrine RFA-1 is effective for weight loss or reducing body fat."
Thanks for your response no I wouldn't pass out completely but I would have little to no recollection after a certain point of the evening I was wondering if others have had similar issues or if it was something else at the time.
I'm not real clear on your term "black out"; are you passing out completely?
While it's never a good idea to drink alcohol with some supplements, there are other things that could have caused you to black out and you should get checked out by a doctor.