Is there any dangerous interaction between xanax (alprazolam) and atenolol??

Define doses used: Dangerous? You mean as in "can kill a person?" Or do you mean to the point where you could pass out, hit your head and have to go to the hospital for a few stitches? There's a potential blood pressure could be lowered more than expected seeing as how atenolol lowers pressure & Xanax (alprazolam) is a sedative type of drug. However, strictly speaking there are no significant interactions betwixt them.