Hydrocodone is an opioid pain medication. Zohydro ER and Hysingla ER are extended-release forms of hydrocodone that are used for around the clock treatment of severe pain. Hydrocodone can slow or stop your breathing. Never use this medicine in larger amounts, or for longer than prescribed. Do not crush, break, or open an extended-release pill. Swallow it whole to avoid exposure to a potentially fatal dose.