Codeine or 3-methylmorphine (a natural isomer of methylated morphine, the other being the semi-synthetic 6-methylmorphine) is an opiate used for its analgesic, antitussive, antidiarrheal, antihypertensive, antianxiety, sedative and hypnotic properties, to suppress premature labor contractions, myocardial infarction as well as many other uses. Codeine is the second-most predominant alkaloid in opium, at up to three percent; it is much more prevalent in the Iranian poppy (Papaver bracteatum), and codeine is extracted from this species in some places although the below-mentioned morphine methylation process is still much more common. It is considered the prototype of the weak to midrange opioids (tramadol, dextropropoxyphene, dihydrocodeine, hydrocodone, oxycodone).
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