There is no one-size-fits-all answer to this question, as the dosage for children and adolescents will vary depending on their age, weight, and health condition. However, a general guideline for treating ADHD is to start with a lower dose and increase gradually until the desired effect is reached. Some common dosages for ADHD drugs are: amphetamine salts (Adderall), methylphenidate (Ritalin), dextroamphetamine (Dexedrine), and lisdexamfetamine (Vyvanse).