Why do bullies have a superiority complex? what kinds of medications work well on bullies?

It's the opposite: Many bullies feel inferior, rather than superior to those bullied. Most bullies, in fact, gave themselves been victims of bullying. There is no effective medication treatment for bullying.

Inferiority: Believe it or not, bullies tend to have inferiority complexes, often from having been bullied themselves. Medication is not the answer; you obviously cannot force the bully to take a pill. Tell someone you know and trust about the bullying/ Keeping it inside does no good.