The dose to be employed is an exceedingly important matter, and one as to which practitioners are still very often injudicious. We ought never to commence with a larger dose than one-sixth of a grain; but very often as little as one-twelfth of a grain will give effective relief, and in not very severe cases it is well worth while to try this smaller quantity. When no larger quantity than one-sixth of a grain is employed we commonly observe no narcotic effects, i. e., there is no contraction of pupil, no heavy stupor, and, although the patient very often falls asleep, on waking he does not experience headache, nor is his tongue foul. I cannot too strongly express the opinion that it is advisable by all means to content ourselves with this degree of the action of hypodermic morphia, unless it fails to produce a decided impression on the pain. But in very severe cases our small doses will fail; and then, rather than allow the patient to continue having severe paroxysms unchecked, we must frankly admit the necessity of using a narcotic dose from one-quarter to one-half of a grain, according to circumstances. Whatever actual dose be employed, it is important not to repeat it with unnecessary frequency; once a day in the milder, and twice a day in the more severe cases, will be all that is advisable, save in very exceptional cases: the point being to administer it as quickly as possible after the commencement of an exacerbation. If by these means we can prevent the patient having any severe pains during a period of several days, we often give time to the affected nerve to recover itself so completely, especially with the aid of other measures to be presently mentioned, that the tendency to neuralgia is completely broken through, and we can drop the injections, either at once or by rapid diminution of the dose, and thereafter treat the case merely with tonics, and with the precautionary measures to be dwelt upon under the heading of Prophylaxis. But, if we have been driven to the use of distinctly narcotic doses, and these do not very speedily break the chain of neuralgic recurrence, it will not do to continue to rely upon hypodermic morphia; it will be best to try some of the local remedies (blistering, galvanism) with it. If this combination fails, we should then try the effect of atropine, the sulphate of which, hypodermically injected, fully represents for all useful purposes the mydriatic class of narcotics.
(b) The commencing hypodermic dose of atropine should be one-one hundred and twentieth grain; it is not often that so small a quantity will do any good, but it is necessary to use this agent with great precaution, as we occasionally meet with subjects in whom extremely small doses provoke most uncomfortable symptoms of atropism, as dry throat, dilated pupil, delirium, and scarlet rash. Commonly we shall find ourselves obliged to increase the dose to one-sixtieth, one-fiftieth, or one-thirtieth of a grain; and in a very few cases it may be necessary to go even as high as the one-sixteenth or one-twelfth. In my experience such instances are excessively uncommon; and I cannot but suppose that the practitioners who use the high doses frequently must inject in such a manner as to fail to get the whole dose taken up. [Absolutely inexplicable to me is the statement of the illustrious Trousseau—that hypodermic remedies are "less active" (!) than gastric remedies—except on his hypothesis.]
The most remarkable effects that I have seen from hypodermic atropia were obtained in cases of peri-uterine neuralgia, especially dysmenorrhœal neuralgia. Speaking generally of atropine, it must undoubtedly be counted far inferior to morphia as a speedy and reliable reliever of neuralgic pain, but for all pelvic neuralgias it appears to me on the whole to surpass morphia. And besides this, in other neuralgias, where opiates altogether disagree (as with some subjects they do), it is not uncommon to find that atropia acts with exceptionally good effect. And to some extent I am inclined to confirm Mr. Hunter's opinion, that, where atropia does stop neuralgia, it does so more permanently than morphia.
There is another special use of hypodermic atropine which I have not seen mentioned by any one but myself, but which is probably very important, namely, in ophthalmic neuralgia where acute iritis, or especially glaucoma, seems coming on. I may be mistaken, but I believe that in three cases I have succeeded, by prompt injection of sulphate of atropine (one-sixtieth to one-fortieth of a grain), in saving a neuralgic eye from damage, and possibly from destruction, from impending glaucoma.
(c) The class of cases for which merely hypnotic remedies are of much value is limited; nevertheless, in the milder kinds of migraine and clavus, especially when they have been brought on or are kept up by mental worry or hysterical excitement, these remedies will sometimes prove very useful. In former days, before we knew chloral, I used to employ camphor for this purpose; three or four grains being administered every two hours: and in hysterical hemicrania of a not very severe type this not unfrequently produced a short sleep, from which the patient awoke free from the pain. But chloral infinitely transcends in value any agent of this kind that was known before. Perfectly valueless for the really severe neuralgias, it is of the greatest possible use as a palliative in migraine and clavus, where the great object, for the moment, is to get the patient to sleep. A single dose of twenty to thirty grains will often effect our object: it may be repeated in two hours if sleep has not been induced; it should be given as soon as the pain has at all decidedly commenced.
And here I wish to make some special remarks on the subject of "palliation," and the relation it bears to "cure." Nothing is more common than to read serious admonitions, in medical works, about the folly of trusting to remedies which only palliate for the moment but leave the root of evil untouched; and, of course, there is a certain respectable modicum of the fire of truth behind all this orthodox smoke. In the case of neuralgia, however, it is most important to understand that mere palliation, that is, stopping of the pain for the moment, may be either most useful or highly injurious, according to the way in which it is done. The unnecessary induction of narcosis for such a purpose, doubtless, is most reprehensible; but if it were possible simply to produce sleep from which the patient should awake refreshed, without any narcotic effects, then, certainly, that sort of palliation must be good. That is precisely what the judicious use of chloral does; and I may mention, as resembling though not equalling it, the action of Indian hemp, which has been particularly recommended by Dr. Reynolds. From one-fourth to one-half of a grain of good extract of cannabis, repeated in two hours if it has not produced sleep, is an excellent remedy in migraine of the young. It is very important, in this disease, that the habit of long neuralgic paroxysms should not be set up; and if the first two or three attacks are promptly stopped, by the induction of sound, non-narcotic sleep, we may get time so to modify the constitution, by tonics and general regimen and diet, as to eradicate the neuralgic disposition, or at least reduce it to a minimum. But I would decidedly express the opinion that such remedies as either opium or belladonna are mostly unsuited to this purpose. If the migraine of young persons does not yield to chloral, to cannabis, or to muriate of ammonia (in twenty or thirty grain doses), it will not be advisable to ply the patient with any remedies of the narcotic-stimulant class, but to trust to tonic regimen and the use of galvanism.
The mention of muriate of ammonia, which, for migraine and clavus and the milder forms of sciatica, not unfrequently proves useful in stopping the violence of a paroxysm and enabling the patient to get some refreshing sleep, leads me to notice that not only may a variety of the milder narcotic-stimulants be employed in this way, but the external stimulus of heat to the extremities (very hot pediluvia) greatly assists the action of any such remedies; especially if mustard-flour be added, so that a mild vapor of mustard rises with the steam and is inhaled. Perhaps the ideal medication, to arrest a bad sick-headache, is to give twenty grains of chloral, and make the patient plunge his feet in very hot mustard-and-water and breathe the steam. He can hardly fail to fall asleep for a longer or shorter time, and awake free from pain.
(d) The use of bromide of potassium in neuralgia is a subject of great importance, and which requires much attention and discrimination. In common with, I dare say, many others, I made extensive trial of this agent when it first began to be much talked of, but was so much disappointed with its effects in neuralgias, that at one time I quite discarded it in the treatment of those affections. Renewed experience has taught me however, that, though its use is restricted, it is extremely effective if given in appropriate cases and in the right manner. For the great majority of neuralgias it is quite useless, and, what is more, proves often so depressing as indirectly to aggravate the susceptibility of the nervous system to pain. The conditions, sine quis non, of its effective employment seem to be the following: The general nervous power, as shown by activity of intelligence, and capacity of muscular exertion and the effective performance of co-ordinated movements, must be fairly good, find the circulation must be of at least average vigor; the patient must not have entered on the period of tissue-degeneration. Among neuralgics who answer to this description, those who will benefit by the bromide are chiefly subjects—especially women—in whom a certain restless hyperactivity of mind and perhaps of body also, seems to be the expression of Nature's unconscious resentment of the neglect of sexual functions. That unhappy class, the young men and young women of high principle and high mental culture to whom marriage is denied by Fate till long after the natural period for it, are especial sufferers in this way and for them the bromide appears to me a remedy of almost unique power. But I wish it to be clearly understood that it is not to the sufferers from the effects of masturbation that I think the remedy specially applicable: on the contrary, it is rather to those who have kept themselves free from this vice, at the expense of a perpetual and almost fierce activity of mind and muscle. The effects of solitary vice are a trite and vulgar story; there is something far more difficult to understand and at the same time far more worth understanding in the unconscious struggles of the organism of a pure minded person with the tyranny of a powerful and unsatisfied sexual system. It is in such cases, which it heeds all the physician's tact to appreciate, that it is sometimes possible to do striking service with bromide of potassium; but it will be necessary to accompany the treatment with strict orders as to generous diet, and, very likely, with the administration of cod-liver oil.
Having decided that bromide of potassium is the proper remedy, we must use it in sufficient doses. Not even epilepsy itself requires more decidedly that bromide, to be useful, shall be given in large doses. It is right to commence with moderate ones (ten to fifteen grains), because we can never tell, beforehand, that our patient is not one of those peculiar subjects in whom that very disagreeable phenomenon—bromic acne—will follow the use of large doses. But we must not expect good results till we reach something like ninety grains daily. Let me add that it is not so far as I know, by reducing any "hyperæsthesia" of the external genitals, of which the patient is aware, that the remedy acts; I have not seen such a nexus of disease and remedy in these cases.
3. Local Measures.—The external remedies which may be applied for the treatment of neuralgia may be divided into (a) skin-stimulants; (b) paralyzers of peripheral sensory nerves; (c) remedies adapted to diminish local congestion; (d) remedies adapted to diminish arterial pulsation; (e) electricity; (f) mechanical means of protection.