Morphine

MORPHINE, the chief alkaloid of opium (q.v.), insoluble in water and ether. It is used in the form of its hydrochloride, sulphate, acetate and tartrate and in various non-official prepara tions such as dionin, heroin, glycaphorm and peronin. The prepa rations of morphine are incompatible with salts of iron, copper and mercury, also with lime water and alkaline earths and sub stances containing tannin. With ferric chloride it forms a deep red colour.

Morphine relieves pain and produces deep sleep. From opium it differs in being less astringent and constipating. No drug yet discovered equals morphine in pain-relieving power. The most frequent mode of administration is the hypodermic, on account of the extreme rapidity with which it is absorbed. In pain due to violent sciatica relief and even permanent cure has been ob tained by the injection of morphine directly into the muscle of the affected part, and in the treatment of renal and hepatic colic, given subcutaneously, it will relieve the acute pain. A violent paroxysm of asthma may be arrested by the administration of morphine subcutaneously, but the practice should not be con tinued, as there is great danger in a chronic disease that the patient may become the victim of morphinism. Morphine is recognized as one of the most useful drugs in the treatment of eclampsia, early injection often arresting the fits. In hxmoptysis morphia is invaluable in quieting the patient and in the cough of phthisis minute doses are of service, though morphine is fre quently better replaced by codeine or heroin, which check irri table coughs without producing narcotism. Its use in Bright's disease is dangerous, minute doses producing disproportionately great results. For the same reason it is not administered to chil dren. In bronchitis with profuse expectoration it checks cough but also checks secretion; where cough is harassing small doses may be necessary to procure sleep, but it must be remembered always that renal disease is often accompanied by bronchitis. In the dyspnoea of advanced valvular disease of the heart morphine relieves the distress and restlessness, and induces sleep. It should, however, be withheld if the heart has undergone fatty degenera tion. If given in excess the drug is eliminated by the intestines and kidneys. It is also excreted in the milk; hence the danger in the administration of large doses of morphine to nursing mothers.

(See POISONS; for morphinism see DRUG ADDICTION.) Morphine-scopolamine anaesthesia was introduced in 19o2 by Steinbiickel. It has been used by some surgeons for the produc tion of anaesthesia previous to the administration of ether or chloroform, but the use of the method is now more usually rele gated to obstetric practice to produce the so-called twilight sleep (see SCOPOLAMINE).

Physical and Chemical Properties.

Morphine, crystallizes from alcohol in colourless prisms, containing one mole cule of water, which is lost at I oo° C. The anhydrous alkaloid melts at 254° C, and has a specific rotation of [a] --13o.9° in methyl alcohol. It is sparingly soluble in most solvents, but dissolves in lime-water and alkalis owing to its acidic character, due to the possession of a phenolic hydroxyl group. (See PHENOL.) It is also a monoacidic base forming salts, which are usually well crystallized. Many of these are manufactured for use in medicine but those most commonly used are the sulphate, and the hydro chloride, which forms colourless, silky needles from water. When morphine or its hydrochloride is heated with hydrochloric acid at 14o° C under pressure, it is converted by loss of a mole cule of water into apomorphine, a substance which has lost the characteristic physiological action of morphine and has acquired that of a powerful emetic, for which purpose it is prin cipally used in medicine. Morphine also yields a number of de rivatives, in which its characteristic physiological action is re tained in a somewhat modified form. Thus when the phenolic hydroxyl group of morphine is methylated, the alkaloid codeine (q.v.), which also occurs naturally in opium, is pro duced. Other derivatives, analogous to codeine, have been made for use in medicine, such as ethylmorphine (dionin), benzyl morphine (peronin). Morphine can also be converted into a diacetyl derivative, known commercially as heroin. The third alkaloid of this group, thebaine, is of importance mainly on ac count of its chemical relationship to morphine and codeine, but is of no value in medicine, since in it the convulsant action feebly manifested in some of the derivatives of morphine is much more strongly developed.