My brother is 16 and he has ADHD. What is the right starting dose for medication?

It is usually better to start low and increase until no additional benefits or side-effects.

Weight can be used to determine maximum dose, 2mg/kg for methylphenidate and 1.5mg/kg for amphetamines.  The following chart was published by Biederman and Wilens at the Harvard department of psychiatry.

More people prefer amphetamines.  Only 16% prefer methyphenidate.  This fits my clinical experience over the past 40 years.  The following chart shows a meta-analysis study that was done that confirms this.

So, if your brother weighs 150 pounds (or 70kg) he may need doses of methyphenidate up to 140mg, or Concerta 54mg 3x per day, or 1-2 Daytrana patches, or 90-150mg Adderall, or Vyvanse 70mg 3x per day for optimal effect.

Over the past several weeks I have tried Vyvanse in over 300 patients, many of whom were previously on Adderall.  The majority of patients prefer Vyvanse – they report that it is smoother, has less side-effects, less rebound in the afternoon, and more efficacy throughout the day.  Vyvanse has less risk to blood pressure or the cardiovascular system and has a mode of action that prevents using it to get high.  There are still some patients that prefer and do better on Adderall.  The lowest dose of Vyvanse is 30mg, which is equal to 10mg of Dexedrine or 20mg of Ritalin (methylphenidate).

How much medication should your brother take?

Enough, not too much.   It takes time and trial and error to find the best dose for each individual.