Vicodin is an analgesic drug contain acetaminophen and hydrocodone (an opioid resembling codeine)

All opiate effects effects are achieved when the substance enters the body and connects to opioid receptors. Once the opioid substance in Vicodin attaches to these sites, a cascade of chemical events transpires - producing the desired effects (lower perception of current pain, suppression of cough reflex, feelings of euphoria, etc.)

In the long-term, Vicodin has the ability to make people overlook the negative side effects while only focusing on the positive effects.