List of products in the National Drug Code with proprietary name . Hydrocodone is used to help relieve severe ongoing pain. Hydrocodone belongs to a class of drugs known as opioid analgesics. It works in the brain to change how your body feels and responds to pain. Do not use the extended-release form of hydrocodone to relieve pain that is mild or that will go away in a few days. This medication is not for occasional ("as needed") use.