Can you tell me is hydrocodone similar to oxycodone?

Similar and differen. They are both semi-synthetic forms of codeine, but have slightly different properties. Oxycodone is more potent, with 5 mg of oxycodone equalling 7.5 mg of hydrocodone. Oxycodone is also better absorbed, and gets into the brain faster, so it works more quickly. It also may produce less histamine release, so that the itching/flushing from Codeine and hydrocodone isn't as prominent in most people.