Paraldehyde.—This is a derivative from ethyl alcohol. It is, when pure, a colorless liquid, with an agreeable odor, somewhat like that of ether. It is soluble in the proportion of one part in eight or nine of water. It may be used internally in doses varying from forty-five to one hundred and sixty grains. A watery solution, containing one part to ten, has been recommended for internal administration. It may also be given in milk or in beer. M. Yvon[43] recommends the following formula:
| Paraldehyde, | Gr. 20.0 | |
| Spirit, | 100.0 | |
| Syr. Simpl., | 75.0 | |
| Tr. Vanillæ, | 5.0 |
An ounce of this mixture contains forty-five grains of paraldehyde. When taken it should be still further diluted with sweetened water, or with beer, to obviate, as far as possible, the disagreeable taste of the drug. Sleep follows after the lapse of about half an hour, and continues from five to seven hours. The physiological action of the medicine is very similar to that of chloral hydrate, and its use is indicated in the same class of cases to which that drug is appropriate. By many it is considered the preferable hypnotic. It has found considerable employment in the insane asylums of Europe, and in other institutions where disagreeable medication is no obstacle to experiment. In private practice the peculiar taste and smell of the article, and its pungent effect upon the mucous membranes of the alimentary canal, render its exhibition more difficult. But the weight of testimony is in its favor as an hypnotic in all cases, uncomplicated with disease of the stomach, in which insomnia is not dependent upon pain, and is associated with cerebral hyperæmia. Its administration is followed by no unpleasant consequences. Among the insane it is particularly recommended during periods of excitement and wakefulness. It has been employed with great satisfaction[44] in cases of insomnia during the course of such varied diseases as emphysema, bronchitis, phthisis, nervous and spinal disorders, diseases of the heart, jaundice, chronic rheumatism, and insomnia from other unrecognized causes. Undoubtedly, with greater skill in its purification and exhibition, it will become one of the most valuable of hypnotic remedies. Almost useless for the relief of pain, it is indicated in cases of uncomplicated insomnia. Having very little power, in moderate doses, to depress the action of the heart, it is preferable to chloral hydrate in cardiac diseases and debility. Sleep procured with doses of fifteen to sixty grains is calm and refreshing, and is not followed by any disagreeable consequence. A certain degree of tolerance is gradually established, so that larger doses may become necessary. It has been given in quantities amounting to three drachms; but, if large doses be given before the development of tolerance, the patient will experience headache, uneasiness, nausea, and vomiting, after waking from the sleep thus induced. Another advantage possessed by paraldehyde consists in the absence of the period of excitement produced by chloral before the advent of sleep. It is an hypnotic, without narcotic properties, limiting its effects chiefly to the brain, and leaving the spinal cord in a condition nearly like that of natural sleep.
Ether, though possessed of the greatest value as an agent for the production of artificial anæsthesia, is rarely used as a mere hypnotic. Diluted with alcohol and ethereal oil, it forms the Compound Spirit of Ether, or Hoffmann’s Anodyne. In this form it is well adapted for internal administration. It is thus very serviceable in the treatment of those forms of insomnia associated with nervous irritability and hysteria. For the relief of wakefulness dependent upon a languid circulation, with cold feet and flatulence, the anodyne may be given in half-drachm doses well diluted with ice water, and repeated every fifteen minutes till relief is obtained. Nearly all forms of painful or spasmodic disturbance unattended by fever may be thus relieved. For this reason it is particularly useful in the treatment of uterine colic and in sleeplessness after childbirth, when opiates cannot be tolerated, or are contra-indicated on account of their tendency to excite the brain.
Chloroform, like ether, is an agent too powerful and too evanescent for use as a simple hypnotic. But for the relief of intense suffering caused by nervous irritation and spasm it is without any superior. In certain minor affections of a spasmodic character it, therefore, forms a valuable adjuvant to other remedies. Diluted with alcohol it forms the spirit of chloroform, a remedy which is useful in all cases for which the compound spirit of ether is usually prescribed. In this form it is an excellent addition to various mixtures designed for the relief of spasmodic coughs by which sleep is disturbed. Ringer recommends it in the treatment of the irritative cough so characteristic of fibroid phthisis. It should also be used in cases of spasmodic asthma. The asthmatic paroxysm may frequently be arrested by inhalations of the vapor of chloroform or ether; but, unfortunately, the lungs soon become tolerant of these agents, and they then cease to afford relief. The valuable mixture known by the name chlorodyne owes a considerable portion of its efficacy to the presence of chloroform as one of its ingredients.
Chloral.—Until the recent introduction of paraldehyde, chloral hydrate has for many years held the first rank as an hypnotic. It is particularly useful in wakefulness occasioned by exhaustion of the nervous centres. The conclusions of all experienced observers have been most concisely stated as follows:[45] “Chloral appears to be indicated when sleeplessness is dependent upon a vascularity due to exhaustion rather than to primary excitement of the brain; thus it has been found useful when loss of sleep follows severe and prolonged mental application or excitement of feeling, or accompanies the general debility following acute diseases attended with delirium or severe pain, or is associated with acute mania, especially of the puerperal form. The somewhat analogous condition which exists in delirium tremens is very amenable to this medicine, especially in the forming stage of the affection known as ‘the horrors,’ and which so frequently follows surgical injuries in drunkards; it is useful also when great nervous excitement and restlessness are associated with extravagant phantasms. Nevertheless, its depressing effects are to be guarded against in this affection as in the different forms of insanity.” This caution is directed against the frequent and repeated employment of the article in chronic cases, on account of the vasomotor paralysis and general cachexia thus induced. It is now claimed that many of these consequences may be avoided by the substitution of paraldehyde in the place of chloral, but it has been shown[46] that similar effects may follow the long continued use of this substitute.
Chloral is usually administered by the mouth in doses, for adults, of twenty to thirty grains, dissolved in sweetened peppermint water. If the first dose does not procure sleep, it may be followed at the expiration of an hour by a second dose of twenty grains. This seldom fails to induce refreshing sleep. When the medicine cannot be tolerated by the stomach it may be given by enema in milk. For this purpose a drachm of chloral should be suspended with the white of an egg in half a teacupful of milk.
Butylchloral hydrate.—This substance has been recommended as a substitute for chloral hydrate, in cases of cardiac weakness, on account of its being less powerful to depress the action of the heart. It is principally useful for the relief of facial neuralgia and hemicrania. As an hypnotic it is seldom used. For this purpose it may be given in a solution like that of chloral hydrate. For a simple anodyne effect the medicine may be given in five-grain doses, repeated every half hour or hour. As a means of procuring sleep it may be given in doses ranging from fifteen to forty-five grains. Liebreich has given the medicine in drachm doses, and recommended it as an hypnotic superior to chloral hydrate. It is useful in the sleeplessness of headaches, neuralgia, dysmenorrhœa, and chronic phthisis.
Amyl nitrite.—This drug has been recommended for the relief of insomnia resulting from the opium habit. Ringer considers it useful in the flushes of heat and other forms of discomfort which sometimes interfere with the sleep of women during the change of life. It should be inhaled in the form of vapor, from a handkerchief upon which five drops have been poured. The quantity will need to be gradually increased, as the system becomes tolerant of its effects. The stimulant effect of the medicine renders its use in this manner probably less dangerous than the similar employment of chloroform. Unlike the other anæsthetics above mentioned, it causes a hyperæmic condition of the brain, and is, for this reason, a useful hypnotic in cases of aortic obstruction with an insufficient cerebral circulation and consequent wakefulness.
Opium and opiates.—There seems to be no agreement among experimental physiologists regarding the manner in which opium produces its effects upon the body. By some it is ranked as a stimulant; by others it is considered a sedative. These different opinions are probably due on the one hand to differences in the dose and strength of the opiates employed, and on the other to idiosyncrasies on the part of the individuals subjected to experiment. The soporific effect of the drug appears to result from its direct action upon the substance of the brain. Under its influence the blood tends to accumulate in the veins, and loses its bright arterial hue. Small doses are said to contract the capillaries of the body, while they are dilated by excessive doses of the drug. From this it may be inferred that opium acts, like many other narcotics, as an irritant of the tissues when given in minute quantity, and as a paralyzing agent when a certain relative amount is exceeded. The experiments of Curci[47] indicate that under the influence of irritating doses of morphia the brain becomes hyperæmic.