This alkaloid is found in opium in concentrations ranging from 0.7 to 2.5 percent.
Most codeine used in the U.S. is produced from morphine.
Compared to morphine, codeine produces less analgesia, sedation and respiratory depression and is frequently taken orally. Codeine is medically prescribed for the relief of moderate pain. Codeine is an effective cough suppressant and is found in a number of liquid preparations. Codeine products are also used to a lesser extent, as an injectable solution for the treatment of pain. It is by far the most widely used, naturally occurring narcotic for medical treatment in the world.