Hydrocodone is a widely prescribed pain reliever, sold under the brand name Vicodin, a combination of hydrocodone and acetaminophen. Hydrocodone is a powerful pain reliever, but it can also be addictive. Extended-release forms of hydrocodone, such as Zohydro ER and Hysingla ER, helps treat severe pain around the clock.Hydrocodone is an opioid that belongs to the class of drugs known as narcotic analgesics.