Get Adderall online delivered to your door in as little as 24 hours. Adderall 20mg is an FDA-approved prescription medication; that is used to treat Attention-deficit hyperactivity disorder (ADHD) and narcolepsy. It can be taken with or without food and should be taken as prescribed by your doctor. It is important to follow your doctor’s instructions and not to increase or decrease the dosage without their approval. Adderall should not be used by anyone under the age of 18.