About Codeine Codeine is a pain reliever that belongs to the opioid family. It is used to alleviate pain that is mild to moderate. Codeine (generic name) Morphinan-6-ol,7,8-dihydro-4,5-epoxy-3-methoxy-17-methyl-(5,6)-, sulphate (2:1) (salt), trihydrate is the chemical formula for Codeine. Each