Hi, Lisdexamfetamine which is more commonly known by its trade name, Vyvanse is a stimulant medication is used to treat ADHD. Mixing alcohol and stimulant medications like Vyvanse often results in an each substance countering the effects of the other. For instance, alcohol minimizes some of the stimulant effects of Vyvanse and Vyvanse reduces some of the sedating effects of alcohol. This can result in an individual using more of one or both the drugs to reach the desired effect, which may lead to a number of potentially dangerous results, including overdose. Side effects of combining alcohol with Vyvanse may include - dramatic changes in the blood pressure, increased heart rate, prolonged vomiting, chest pains, dilated pupils, dry mouth, dry nose, hyperactivity, irritability, aggression, fatigue, weakness, confusion, delusion, hallucinations, heart attack, seizures etc. If someone experiences such type of side effects, he or she should immediately consult the doctor for urgent medical help. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician