Green Xanax is used to treat anxiety disorders and panic disorders. calms down your nervous system. It’s in a class of drugs called benzodiazepines and works by lessening abnormal excitement in the brain. Xanax is available in the form of 1mg,2mg,3mg, and 0.5mg. Blue Xanax may cause serious side effects including depressed mood, confusion, and agitation. Do not take it more often than directed.