That is what Satovan is saying, the hydrocodone is the opioid in Vicodin or generic formulations that produces a buzz at higher doses. Typically the dose for a buzz is 20-30mg of hydrocodone or about five 5mg pills. Each pill also has 500mg of acetaminophen which is not psychoactive and is hepatoxic at high doses.
Unless you have a low tolerance don't waste your time with 5/500s, get 10mg pills or get yourself some heroin (which will also save you some money).