Definition And History

Many substances with high pharmacological activity can be extracted from the plant Papaver somniferum, known popularly as 'poppies'. By cutting the papaver somniferum pod when it is still green, a milky juice can be obtained, and that is the opium (the word opium in Greek means juice).

When dried, this juice is called opium powder. It contains several highly active substances. The most known is the morphine. The word 'morphine' derives from the greek mythologic God Morpheus, the God of the dreams.

One can easily figure out the effects of opium and morphine by their names. Morphine -> dream; somniferum -> from the latin meaning 'sleep inducer'. In other words, they're depressors of the Central Nervous System (or CNS), and make the brain function at a slower pace than normal. But opium still contain other substances, and codeine is also well known. It is still possible to obtain another substance, heroin, when making a small chemical modification in morphine's formula. Hence, heroin is a semi-synthetic substance (or semi-natural).

These substances are called opiate drugs or just opiates, for they come from the opium; they can be natural opiates when they don't suffer any modification (morphine, codeine), or semi-synthetic opiates when they are resultant from partial modifications of the natural substances (as in the case of heroin).

But the human being was capable of imitating nature by manufacturing in laboratories several substances with similar action of opiates: meperidine, propoxiphene and methadone are just a few examples. These completely synthetic substances are called opioids (meaning: "similar to opiates").

All these substances are put into capsules, pills or vials, becoming medicine.