Definitions and Terminology

Morphine belongs to a large group of drugs designated in pharmacology as narcotics. In therapy a distinction is usually made between four principal types of narcotic - ([1] ) analgesics(pain-killing drugs), ([2] ) hypnotics(sleep-inducing drugs), ([3] ) sedatives(soothing drugs) and ([4] ) anaesthetics(drugs inducing unconsciousness). The lines of demarcation between these groups are not clearly drawn, and depend usually in part on the size of the dose.

Administered in proper doses and at the appropriate time, morphine can act either as a sedative, as a hypnotic, or-particularly in combination with other drugs-as an anaesthetic (for example, morphine-scopolamine in basal narcosis).1

Pharmacognosy is the study of crude medicinal drugs-i.e., the raw materials of vegetable and animal origin which are used directly for medicinal purposes or in the manufacture of pharmaceutical preparations.

Nevertheless, its most striking feature is its analgesic action-Therefore the present article is restricted to a discussion of the analgesic properties of morphine and morphine-like substances.

CLASSIFICATION

Natural drugs with morphine-like effects
Opium and medicinal preparations of opium, poppy straw (or poppy capsules), morphine and the principal secondary opium alkaloids.

Semi-synthetic drugs with morphine-like effects (derivatives of opium alkaloids)

For example: Benzylmorphine (peronine), ethylmorphine (dionine), diacetylmorphine (heroin), dihydrodesoxymorphine-D (desomorphine), ethyldihydromorphinone, methyldihydromorphinone, (metopon), monoacetylmorphine, α-isomorphine, β-isomorphine, γ-isomorphine, tetrahydroxydesoxymorphine, dihydromorphinone (dilaudid), allopseudocodeine, heterocodeine, isocodeine, pseudocodeine, dihydrocodeinone (dicodid), dihydrohydroxycodeinone (eucodal), morpholinylethylmorphine (pholcodin).

Synthetic drugs with morphine-like effects ([4] )

For example, representatives from the pethidine group, the methadone group, the morphinan group and the dithienylbutenylamine group.

The substances from these groups are prepared exclusively by synthesis from common chemicals not related to the poppy plant.