The purpose of this combo drug is to treat moderate to severe pain. Both an opioid painkiller (hydrocodone) and a non-opioid painkiller are present. The brain-based effects of hydrocodone alter how your body perceives and reacts to pain. Additionally, acetaminophen helps lower a fever. The extended-release hydrocodone medications Zohydro ER and Hysingla ER are used to relieve severe pain round-the-clock. Hydrocodone with extended-release should not be taken for pain on an as-needed basis.