ABSTRACT
Opium, the juice of the opium poppy, Papaver somniferum, consists of a mixture of chemicals. The major pure drug in opium is morphine; codeine also occurs naturally. Chemists have modified the morphine and codeine molecules to make other 'opiates' with generally similar actions, such as heroin (diacetylmorphine) and hydromorphone. In the late 1930s, German chemists synthesized several drugs (methadone, pethidine) which while not in any way derived from opium had almost all of the pharmacological actions of morphine and other opiates. The term opioid was then proposed to include both the opiates and their synthetic surrogates.
