Managing severe pain. Norco 7.5-325 mg extended-release tablets are only for use when continuous (around-the-clock) treatment is needed for a long time. It is also only for use when other pain treatments do not treat your pain well enough or you cannot take them. It is Not for use right after surgery if you have not already been using narcotic pain medicines, if you need only occasional or as-needed pain relief, or if the pain is mild or is not expected to last for a long time. Opana ER extended-release tablets are a narcotic (opioid) pain medicine. It works in the brain and nervous system to reduce pain.