Alprazolam 0.5 mg is used for anxiety disorders and panic disorders, and anxiety caused by depression, such as sudden and unexpected attacks. Alprazolam is a benzodiazepine. It is thought that it works by enhancing the activity of certain neurotransmitters in the brain. Some side effects are signs of an allergic reaction to alprazolam: hives; difficulty breathing; swelling of your face, lips, and tongue. After you take this medicine, do not drink alcohol while taking alprazolam. The risk of serious problems such as severe dizziness, sleepiness, trouble breathing, coma, and death may be higher if you drink alcohol while taking alprazolam.