Hydrocodone/acetaminophen is not only the most commonly prescribed opioid in the United States but also the most common prescription medication written in America. Although original and early trials confirmed its ability to manage acute pain from surgery and musculoskeletal injury, it is perhaps more widely used today in the management of chronic pain. However, the opioid product was introduced for the management of moderate to moderately severe pain. Because it has been greatly abused as a prescription opioid medication, physicians need to be aware of the current knowledge regarding this analgesic drug. This review summarizes the current knowledge of the pharmacokinetics, pharmacodynamics, and metabolism of hydrocodone. Recent information regarding the possibility of hydrocodone as a prodrug for hydromorphone is discussed. The available clinical trials for the use of hydrocodone in the management of acute, chronic, and cancer pain are presented.