Hydrocodone is an opioid pain medication used to treat moderate to severe pain. It works by binding to opioid receptors in the brain and nervous system to reduce the perception of pain. Hydrocodone is often combined with other pain relievers, such as acetaminophen, to enhance its effectiveness. It can be habit-forming and is typically prescribed for short-term use due to the risk of addiction and dependence. Common side effects include dizziness, drowsiness, constipation, and nausea.