- a white, crystalline, slightly bitter alkaloid, C18H21NO3, obtained from opium, used in medicine chiefly as an analgesic or sedative and to inhibit coughing.
- a white crystalline alkaloid prepared mainly from morphine and having a similar but milder action. It is used as an analgesic, an antidiarrhoeal, and to relieve coughing. Formula: C 18 H 21 NO 3
