This section is from the book "Materia Medica And Therapeutics - Vegetable Kingdom", by Charles D. F. Phillips. Also available from Amazon: Materia Medica And Therapeutics: Vegetable Kingdom.
The hydrochlorate of quinine is evidently the best preparation, especially for the purposes last named. The formula of the neutral salt is C20H14N2O2, HCL+2H1O. It is soluble in as little as 24 parts of water, and is a good deal less irritating to the stomach than the sulphate. It is fully as active, probably rather more so, than the latter: hence its dose as an ordinary tonic may be reckoned as one to two grains thrice daily; as an anti-neuralgic, from three to twenty grains (according to the circumstances described above); and in the acute septic diseases, according to Binz, Socin, and others, who have come to employ it to the exclusion of all other quinine salts, it may be given up to the quantity of sixty to one hundred and twenty grains in the twenty-four hours. The neutral salt, it must be remembered, should be crystalline; the acid hydrochlorate forms a gummy amorphous mass, and is not a desirable drug.
If We wish to produce the specific effects of quinine there is no reason to suppose that any of the other very numerous salts of that alkaloid have any advantage over those already mentioned. With regard to the hypodermic injection of quinine, which is becoming important, I am sorry that it is not easy to give any thoroughly satisfactory directions. Ordinary sulphate of quinine, in order to be made sufficiently soluble to be got into the necessarily small quantity of water that can be used for this purpose, requires some other powerful solvent; and, whatever solvent may be chosen, the resulting liquid will to most persons prove so irritant that the formation of an abscess, or at least a hard, painful swelling with a black cicatrix in the centre, is pretty certain. Neither sulphuric, nor acetic, nor (in spite of Bricheteau's assertion) tartaric acid can be used for this purpose, without at least an even chance of producing painful local inflammation.
Probably a plain aqueous solution of the neutral hydrochlorate is the best form for giving quinine subcutaneously. It is true that in order to inject as much as one grain we shall have to use about twenty-five minims of distilled water, but the operation will be entirely painless, provided the needle terminates in a flat-bladed steel point (Buzzard's); and one grain given in this way is at least the equal of three, if not of four, grains given by the mouth. It will therefore be understood that even motives of economy might not unfrequently induce us to adopt the subcutaneous method, and there is also the advantage of not irritating the stomach.
Of the other salts of quinine I shall simply mention the names, since I distrust the statements as to their special virtues.
Besides these there are other salts of quinine which are rather to be considered as preparations of some other substances. The arseniate, the antimoniate, the hydriodate, etc., must be thus looked upon. In short, the ingenuity of chemists has been somewhat unprofitably exercised (so far as mere pharmaceutical purposes are concerned) in multiplying preparations of this alkaloid without any good reason or result.
It should have been mentioned just now that quinine can be very readily given by inhalation of solutions, and that this procedure is very useful in many conditions of the larynx, bronchi, and air-cells in which a local antiseptic effect is required. A convenient method is to dissolve eight grains of hydrochlorate or sixteen grains of sulphate of quinine in twenty ounces of distilled water: this solution gives a very good spray for inhalation.
With regard to one particular preparation of quinine, the so-called citrate of quinine and iron, a few words must be specially said. It is to be regretted, but is certainly true, that this article is so irregularly made that few physicians are justified in prescribing it. There are many wholesale chemists who sell two qualities of this drug ("A" and "B"), the cheaper of which is simply an imposture, containing little if any quinine.
In fact, if it be wished to administer iron and quinine together, we shall do better to mix for ourselves. Sulphate of iron and sulphate of quinine can be given together, in mixture or in pills; and citrate of iron can be given with quinine in effervescence with citric acid and potash or ammonia.
Of Quinidine it is known, especially from the late Indian researches, that the sulphate acts much in the same way and with the same energy as sulphate of quinine. It is also very fairly soluble in water (1 in 108), so that for administration by the stomach it is a convenient salt. The doses are the same as those of quinine.
It is necessary, however, to be sure that we really get the article wished for, as (at any rate till quite lately) the so-called sulphate of quinidine of the shops was in many cases sulphate of cinchonidine. The quinidine salt should yield the tests above mentioned.
Cinchonine is met with here almost exclusivelv in the form of the sulphate. The neutral sulphate, 2C20H14N2O,SH1O4 + 2H1O, is soluble in 66 parts of cold water, and does well for internal use; the dose must be at least twice as large as that of quinine or quinidine salts. The acid sulphate, C20H14N2O2,SH1O4 + 4H1O, is far more soluble still, and is a very convenient substance for hypodermic injection in neuralgias, as well as in intermittent fevers, etc. From one to five or six grains may be thus very easily injected with water. Still, like all the cinchona alkaloids, it has some tendency to irritate the subcutaneous tissues.
Cinchonidine Sulphate, as already mentioned, has very often been sold in the shops for quinidine sulphate. Its action is in every way similar to that of the latter, but it is slightly (perhaps one-sixth or one-eighth) weaker than quinine or quinidine salts.
Quinovic Acid, under the form of quinovate of lime, already referred to, can now be readily procured in London. The dose in powder is two to eight grains every hour, for diarrhoea and dysentery. For solution, Messrs. Hodgkinson & Co. recommend the following formula:
R Calcis quinovatis, gr. 96. Pulvis tragacanth., gr. 10. Acid. phosph. dil., q.s. Aqua, 3 vj. Misce.
Of the various other cinchona substances, more especially the bark-tannins, I have no sufficiently accurate knowledge to say anything about the form of preparation or the dose.