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.
In affections of this nature, the stimulant influence of opium on the nervous system renders it peculiarly efficacious. Perhaps under this head we might rank the collapse of the initial stage or chill of certain febrile diseases; but enough has been said on that subject already.
Insanity often presents conditions in which this influence of opium is extremely useful.
There is a species of delirium resulting from extreme fatigue, long watching, exhausting indulgences, excessive study, etc., for which this is the most efficient remedy, combined with measures calculated to restore strength. Such attacks of delirium occasionally supervene upon acute diseases, especially those of a febrile character, and are very liable to be mistakenly ascribed to active congestion or irritation of the brain. I have seen it occur in acute rheumatism, and cause serious apprehensions of rheumatic meningitis. I have also seen such a condition occur in erysipelas, with a sudden disappearance of the local inflammation, and with signs of great prostration. The relief obtained, in all such cases, from full doses of opium, is a sufficient proof of their nature. It is usually advisable to combine the opium with ipecacuanha, so as to modify its stimulant effect, should the diagnosis prove to have been erroneous.
Delirium tremens is an example of the same condition of the brain, induced in drunkards by the abstraction of their wonted stimulus. In this affection, I regard opium as the most valuable remedy in our possession. Given in the dose of about two grains, repeated every two hours, it will almost always, in the uncomplicated cases, induce sleep from which the patient will awake improved, if not quite cured. Sometimes two or three days may elapse before the effect is produced; but no injury results, if the opium is withheld upon the first occurrence of narcotic symptoms. It is seldom necessary to exceed the amount stated. Injurious cerebral effects have been ascribed to the use of opium in delirium tremens; but I have not seen them, though much of the disease has come under my notice. Where they have occurred, I presume that the meningitis of drunkards has been mistaken for pure delirium tremens; a mistake which may be readily made, as the symptoms of the latter disease are almost always, and necessarily intermingled with it. But, while the opium is given as the main remedy, sufficient alcoholic drink should be administered to prevent prostration. I have seen death result apparently from a neglect of this precaution.
Most of the affections already referred to, as the result of nervous irritation, may proceed also from debility or depression of the nervous centres; and. as the former yield to the indirect sedative property of opium, so do the latter to its direct stimulant action. Muscular tremors, spasmodic and convulsive affections, wakefulness, general uneasiness, restlessness, depression of spirits, palpitation of the heart, dyspnoea, various abnormal sounds and visual disorders, vertigo, and headache, are some of the affections referred to. As a proof that they are really the effects of weakness or depression, they come on frequently as the direct consequences of a debilitated state of system, as in convalescence from exhausting diseases, after hemorrhages or copious bleeding, and under the direct influence of sedative poisons, as tobacco and hydrocyanic acid. They generally yield, at least temporarily, to moderate doses of opium.
In these affections opium is one of the most efficient means employed, and, whatever other remedies may be used, is very often combined with them. It probably operates, through its indirect sedative agency, in allaying irritation in the part affected, and diminishing the activity of the capillaries. The morbid discharges are either, in the first place, secretory or excretory, or secondly, hemorrhagic. To the first category belong diarrhoea, the different forms of cholera, diuresis and diabetes, gastrorrhoea, cystirrhoea, bronchorrhoea, and ptyalism.
In diarrhoea and cholera opium acts not only by restraining secretion. but also by diminishing the activity of the peristaltic movement, probably through a sedative agency in relation to the organic nervous centres. Of its use in diarrhoea dependent on acute inflammation or vascular irritation of the alimentary mucous membrane enough has been said already. But there is no form of that affection in which it may not be usefully employed, except, simply, in cases in which the affection is acting beneficially, either by diverting disease from some part where it might do more harm, relieving plethora, or promoting the absorption of effused fluid, as in dropsy. In all these cases, opium may prove injurious by prematurely arresting the discharge, and should be resorted, to only to regulate the amount of it, and to control it when likely to do more injury by exhausting the patient, than good in either of the modes mentioned. In bilious diarrhoea, it acts upon the liver as well as on the bowels; but in general should not be used alone, as the excess of the bilious secretion is probably relieving hepatic congestion, and its suppression might endanger an attack of hepatitis. Under such circumstances, it should always be associated with small doses of calomel, which, while the opium restrains the secretory function of the liver, has the effect of preventing its entire suspension, and, at the same time, acts as an alterative upon the gland. The best method of administering the two remedies, in this-affection, is to give very small doses of each, very frequently repeated; so that their operation may not be too powerful at once, and may be more conveniently watched, and timely checked, if desirable. One-sixth of a grain of each may be given every hour or two, till the desired effect is produced, or a grain or two have been administered; and it is often a good plan to intermit the treatment every other day, resorting, in the intermediate day, if the discharges have been arrested, to a mild laxative. In the diarrhoea attended with copious light-coloured discharges. which are sometimes very profuse and exhausting, opium is equally indicated as in the former case; and there is a still stronger call for the conjoint use of calomel, in order to restore the hepatic function, and thus unload the portal veins through their natural outlet. In chronic diarrhoeas, whether dependent on relaxation, mere habit, or chronic inflammation or ulceration, opium in small doses, though it cannot be depended on for the cure, is an almost essential adjuvant of the astringents and alteratives employed; and, in full dose, combined with ipecacuanha at night, operates very usefully by superadding to its direct influence on the peristaltic movement a revulsive influence towards the surface.