Are There Any Side Effects From ADHD Medications?

I know a child who is taking methalphenadate (bad spelling) for add adhd he seems to be having attacks of anxiety and hostile rages verbally and occasionally show physical aggression related to these attacks. The side effects of methalphenadate seem to be the cause of these times. is it possible that them meds are causing this problem? fast heart rate and pounding heart are also part of his issues. sometimes this is brought on by simple social conflict. please help me