This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
The pharmacology of quinine is the same in all of its compounds; but certain quinine derivatives possess advantages. Some are tasteless, and others do not disturb the stomach, since they are not absorbed until after reaching the intestinal tract. Double salts possess advantages for hypodermic use.
Aristochin is a di-quinine carbonic ester, nearly tasteless but absorbed from the intestinal tract. Dosage and indications the same as quinine.
Euquinine is quinine ethyl carbonate, a tasteless product of the same class as the preceding.
Quinine Dihydrochloride is very soluble and is useful for subcutaneous injection and when rapid absorption is necessary. Uses are the same as other salts and given in the same dosage. This salt can be procured in sterile ampule form ready for hypodermatic administration.
Quinine Tannate is tasteless. It is given to children and used otherwise when an insoluble salt is desired. It must be given in double the dose of the sulphate.
Saloquinine is a quinine salicylic ester and is a tasteless substitute for quinine. Dose, 5 to 20 grains. The salicylate of the same is given in somewhat less dosage - up to 15 grains.
Quinine and Urea Hydrochloride contains 60 per cent of anhydrous quinine and is relatively non-irritating. It is readily used by hypodermic injection in the treatment of malaria, and the dosage is that of the other quinine salts. This product may be used internally just as are other salts.
Applied to mucous membranes, this salt is locally anesthetic in solutions of a strength of ten to twenty per cent. It is inferior to cocaine as a local anesthetic but serves a useful purpose, especially since the anesthesia is very lasting. This is an advantage in treating painful affections, but a disadvantage when mere transient anesthesia is desired.
By hypodermic injection the anesthesia is very prolonged, sometimes persisting for several days; but the salt is very irritating to some of the tissues, producing fibrous indurations. This property is made use of by some surgeons in the treatment of hemorrhoids and goiter. Be sure to employ only the best of technic, as outlined in recent text-books on surgery. One per cent solutions are as strong as should be injected for the production of local anesthesia, and even this strength is very apt to be irritating. Many cases have been reported in which trouble arose from the use of this percentage in the production of local anesthesia.
For the general practitioner of medicine, and especially when the tissues are of low vitality, it is well to use a 0.25 per cent solution; but one of 0.50 per cent is usually considered safe.