This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
It will be recollected that I consider the sedative effect, produced by large doses of quinia, as essentially secondary; being always preceded by a longer or shorter period of excitement in certain cerebral centres, and probably dependent, at least in some degree, on this previous excitement, overwhelming, and as it were paralysing these centres, and disabling them from extending their normal influence to the organic functions generally. In reference to this sedative property of quinia, it would seem to be applicable generally to diseases of over-excitement, not connected with active congestion, inflammation, or peculiar excitability of the brain. Some, who believe in the direct sedative power of the medicine, do not admit even this exception. By these it is recommended in all inflammatory affections, even those of the encepha-lon; but experience has shown that it may prove very injurious, and even fatal, in such cases. The quantity requisite for the production of the secondary depression varies from fifteen to sixty grains daily. From a less amount, there might be danger of obtaining the direct stimulating effects of the medicine. The following are the complaints in which quinia has been especially recommended as a sedative.
Fevers. There can be no doubt that large doses of quinia will often control febrile phenomena, reducing the frequency and force of the pulse diminishing the heat and dryness of the surface, and sometimes even relieving headache and delirium. Carried far enough, it will suppress all signs of over-excitement, and may even bring on great prostration.
In remittent miasmatic fever it is thus employed, especially in our Southern and South-Western States, very soon after the commencement of the disease, before a remission has become decidedly established, and even in the height of the paroxysm. There can be no doubt, from the abundant testimony on the subject, that, thus given, it will often speedily put an end to the febrile phenomena by its sedative operation; while, through its antiperiodic powers, it prevents a return of the paroxysms, and thus cures the disease. The effects are, in very numerous cases, so prompt and happy, and the injurious results comparatively so few, that the practice has become very popular, and, in some districts, almost exclusive. But, if my views of the action of quinia in these cases are correct, it is not without its dangers. Should active congestion, or positive inflammation of the brain, complicate the disease, it might be fatally aggravated, especially if it should happen to be seated, not in the lobes, which are comparatively little affected by quinia, but near the base of the brain, in the centres of vision and hearing, and of the great organic functions, which it powerfully excites. Even without the positive existence of high vascular irritation or inflammation, a simple morbid tendency to these conditions might be goaded into dangerous action. This is not pure theory. One case at least is on record, in which fatal encephalitis, in an attack of miasmatic fever, was ascribed to the excessive use of quinia (Baldwin, Am. Journ. of Med. Sci., N. S., xiii. 293); and, were unfavourable results as often noted as the favourable, it is not improbable that others might be adduced. It seems to me, therefore, a safer practice, in these fevers, to wait for a decided remission before prescribing quinia. The only exceptions I would make to this rule are cases, either originally pernicious, or becoming so in the course of the disease. In these, the danger of a fatal issue is imminent, and there is little risk of inducing active cerebral congestion or inflammation; as the tendencies are asthenic rather than otherwise, and the disposition much greater to nervous prostration and passive congestion, than to inflammatory action. In the pernicious remittent, therefore, or congestive fever of the South, quinia may be given freely after reaction has taken place, and before the occurrence of a distinct remission; and the main error to be guarded against is the exhibition of the remedy, in overwhelming doses, during the cold stage, or that of prostration, for fear of fatally aggravating the existing depression, by the indirect sedative influence of the quinia.
In yellow fever, also, quinia has been largely employed in this country, upon the same principle; that, namely, of suppressing the fever by its sedative influence. Given in doses of fifteen, twenty, or thirty grains, at an early stage of this complaint, it will undoubtedly often relieve and even remove the febrile phenomena; and, if the disease be moderate, and spontaneously curable, the patient will experience little subsequent inconvenience. But experience has shown that, though it may suppress the febrile symptoms, it is incapable of controlling those deeper derangements, and especially that depravation of the blood, in which the chief danger consists; and, in serious cases, the patient dies with prostration, hemorrhage, black vomit, etc., quite as certainly as though no quinia had been given. There is even reason for believing that the great secondary depression, resulting from the overwhelming doses sometimes used, may, when superadded to the debility of the second stage of the disease, produce a fatal result in cases, which, if otherwise treated, might end in recovery. There is, moreover, the risk of seriously aggravating any inflammatory condition or tendency which may exist in the brain, in the early stage, and of still further irritating the mucous membrane of the stomach, already perhaps the seat of high vascular irritation, if not of inflammation. The reader will perceive, therefore, that the sedative treatment by quinia is not that which I am disposed to recommend in yellow fever; though it is proper to state, that my conclusions have been deduced from & priori reasoning, and the recorded experience of others, and not from any experience of my own with this mode of treatment.