Official drug information tells people not to drink alcohol while taking Adderall, because alcohol can worsen the medication's side effects and both together add strain on your heart.
The authoritative U.S. patient information from MedlinePlus (National Library of Medicine) flatly states, "do not drink alcohol while you are taking amphetamine. Alcohol can make the side effects from amphetamine worse," which lands this at avoid rather than merely caution. Adderall is a central-nervous-system stimulant (dextroamphetamine/amphetamine), and its FDA label (DailyMed) documents that CNS stimulants raise blood pressure (mean increase about 2 to 4 mm Hg) and heart rate (mean increase about 3 to 6 bpm), with some patients seeing larger increases. Because a stimulant can blunt the sedating feeling of alcohol, people may not realize how intoxicated they are and drink more, pushing cardiovascular strain further in the wrong direction. The UK regulatory label (MHRA/emc) is consistent, stating that alcohol may exacerbate the CNS adverse reactions of dexamfetamine and that patients are advised to abstain from alcohol during treatment. None of these official sources give a "safe amount" or a green light, and MedlinePlus notes that a personal or family history of heavy alcohol use is a reason a doctor will probably not prescribe this medication at all.
Who should not drink at all: anyone with heart problems, high blood pressure, or a heart-rhythm disorder, since the FDA label warns of possible serious heart problems or sudden death with stimulants, and alcohol adds risk; also avoid entirely if you have any history of alcohol misuse, since Adderall is habit-forming. Warning signs to stop and seek help: a fast, pounding, or irregular heartbeat; chest pain; shortness of breath; fainting; or severe anxiety, agitation, or confusion — and because the stimulant can hide how drunk you feel, treat "I don't feel it yet" as a reason to stop, not to keep drinking. Timing: the official sources do not state a specific number of hours to wait between Adderall and alcohol, so don't assume a "spacing" window is safe — their guidance is to abstain during treatment. When to call a clinician: promptly if you get chest pain, trouble breathing, fainting, or a racing/irregular heart after mixing the two; and beforehand, ask your prescriber or pharmacist whether any alcohol is acceptable given your dose, heart health, and other medications.
This is general reference, not medical advice, and not a guarantee of safety. Interactions depend on your doses, health conditions, and other medicines. Always confirm with your pharmacist or doctor before combining products, and follow the dosing on each label.