codeine, alkaloid found in opium. It is a narcotic whose effects, though less potent, resemble those of morphine. An effective cough suppressant, it is mainly used in cough medicines. Like other narcotics, codeine is addictive. See drug addiction and drug abuse.

Heterocyclic compound, a naturally occurring alkaloid found in opium, used in medicine as a cough suppressant and analgesic drug. It exerts its effects by acting on the central nervous system (brain and spinal cord). Chemically it is methylmorphine, the methyl ether of morphine, an alkaloid of the phenanthrene type; its action is weaker than that of morphine, and it is less likely to lead to drug addiction.

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