Chloral,—Chloral (Chloral Hydrate).

Other tomes: Petersen

Chloral itself is Tri-chlor-aldehyde, (C2HCl3O), an unstable, oily, colorless fluid, formed by the action of Chlorine upon Alcohol. Its Hydrate, the official Chloral, (C2HCl3O + H20), is a white crystalline solid, soluble in Alcohol, Water, and Glycerin, and is decomposed by alkalies into Chloroform and a Formiate of the alkaline base.

Dose of Chloral Hydrate varies much with individual susceptibility and with the presence or absence of cardiac and pulmonary disease. An average dose for a healthy adult may be placed at gr. xv-xx,—for a child gr. j for each year of age, up to gr. vj. It is best given in Syrup of Tolu, and should be well diluted. Poisonous symptoms have followed the administration of gr. xxx, and in one case after only gr. vijss. When tolerance has been established by habitual use, as much as ʒiij have been taken daily, for months.

Hypnotic Analogues of Chloral.

Paraldehydum, Paraldehyde, C6H12O3,—is a polymeric form of Ethylic Aldehyde (C2H4O), obtained by treating the latter with dilute sulphuric acid. It is a pungent fluid, of somewhat unpleasant odor and taste, soluble in 8 ½ of water, and miscible, in all proportions, with alcohol, ether and oils. It is a reliable hypnotic, fully equal to Chloral, but of shorter action, requiring more frequent repetition to produce sustained sleep. It is unquestionably safer than Chloral, as in medicinal doses it slows and strengthens the heart, and leaves no unpleasant after-effects, except a disagreeable odor to the breath. In very large dosage it is paralyzant to both heart and respiration. It occasionally causes an erythematous eruption, and may give rise to cerebral congestion and vaso-motor paralysis, if used for any long period. Dose, ♏xxx-ʒij in water, syrup, etc.,—ʒj being about the average hypnotic dose for an adult.

*Chloral Butylicum, Butyl-chloral Hydrate, Croton-Chloral, C4H5Cl3O + H2O,—is a crystalline body formed by acting on Aldehyde with Chlorine. It is sparingly soluble in water, (1 in 100), but is readily so in glycerin (1 in 4). In action it closely resembles Chloral, but is feebler, less depressant to the heart, and generally less poisonous, but more disagreeable to the taste. It is said to specifically affect the fifth nerve, and to cause anaesthesia over its distribution long before producing general anaesthesia (Leibreich ). Dose, as hypnotic, gr. v-xx.

*Chloralamid, Chloral Formidate,—is a union of Chloral Anhydride with Formamide, occurring as colorless crystals decomposed in hot or warm solutions, soluble in 20 Of water and in 1 ½ of alcohol. Dose, gr. x-xlv; an average adult hypnotic dose being about 30 grains, given in a little brandy and water. Is a proprietary drug, having been patented and trade-marked, wherever possible, by its manufacturer, Schering, of Berlin.

*Urethan, Ethyl Carbamate, NH2CO2C2H5,—occurs in crystals which are readily soluble in water, with scarcely any taste or odor. It is devoid of irritant action, and may be administered hypodermically. It is a pure hypnotic, but not so reliable as paraldehyde or chloral; neither does it affect the circulation nor depress (but rather stimulates) the respiration. It acts directly on the cerebrum, causing a sleep which closely resembles the normal, and has no unpleasant after-effects. In very large doses it slows the heart, lowers the temperature, and induces muscular resolution and general anaesthesia. In small animals it effectually antagonizes the action of Strychnine. Dose, gr. xv-ʒj, an average hypnotic dose being gr. xxx; but it is best given in 5-grain doses repeated frequently, as a large dose may cause vomiting.

*Somnal,—is a liquid formed by the union of Chloral, Alcohol and Urethan, occurring as a colorless liquid, resembling chloroform in its behavior with cold water, refusing to mix or dissolve, and forming globules therein. It is soluble in alcohol, in alcoholic solutions and in hot water. Doses of 45 and even 60 minims produced no depression of the circulation or respiration. In doses of ʒss its action is usually very prompt, the dose is well borne always, easily taken (in a little syrup of tolu or whiskey), and entirely without deleterious effect. The effects are much more striking and certain than those of Urethan, and far less depressing than those of Chloral; and there is no vertigo or depression, as may follow the use of Sulphonal.

*Sulphonal, Diethyl-sulphon-dimethyl-methane, C7H16S2O4,—belongs to the group of Disulphones, and is a white, crystalline substance without odor or taste, very slightly soluble in cold water, more so in warm water, and still more so in alcohol, ether, etc. The dose is gr. xv-xlv, in hot soup or milk, coffee, tea, etc., administered two hours before the effect is desired. Sulphonal is said to have no intoxicant or narcotic action, and no unfavorable effect on the heart or circulation, even in full doses. It is an admirable hypnotic in many cases, but its efficacy decreases with use.

*Trional,—differs from Sulphonal only in the substitution of an ethyl for a methyl group, and occurs in lustrous, bitter, tabular crystals, sparingly soluble in water, readily so in alcohol and in alcoholic solutions. It is an efficient hypnotic, less liable than Sulphonal to cause ill effects, but must be given in doses fully as large, gr. xv-xl. A potent objection to its use is the fact that it is patented by its manufacturer.

*Hypnone, Phenyl-methyl-acetone, C6H5(CO)(CH3),—a member of the Ketones, (see ante, page 133), occurring above 70° F. as a colorless, mobile liquid, having a strong almond and orange odor. It is insoluble in water or glycerin, and is best given in capsules. It is a hypnotic, of only moderate intensity, but said to be especially useful in the insomnia of alcoholism. Its use is devoid of danger, and leaves behind no unpleasant effects, except a disagreeable odor of the breath, the drug being eliminated by the lungs as well as by the kidneys. In very large dosage it has induced coma, followed by paralysis of the heart and respiration. Dose, ♏v-x, in capsule, ♏vij to ♏viij being usually required.

* Amylene Hydrate, Di-methyl-ethyl-carbinol, C5H12O,— a tertiary alcohol, occurring as a clear, colorless fluid, of peculiar odor, soluble in 8 of water and readily miscible with alcohol. It is one of the most valuable hypnotics, in power standing between chloral and paraldehyde, but being much more agreeable to the taste and safer than either of those agents. Its action is exerted chiefly on the cerebrum in doses sufficient to produce profound narcosis; and in medicinal doses it leaves behind no unpleasant effects, and has no perceptible influence on the heart or respiration. By very large dosage the medullary centres are paralyzed, including those governing respiration and cardiac action. Dose, ʒj-ʒjss.

*Methylal, Methylene-di-methyl Ether, CH2(OCH3)2,—one of the products of the oxidation of Methylic Alcohol, occurring as a volatile, mobile liquid of pleasant, aromatic odor and taste, readily soluble in water, alcohol, etc. It is a local anaesthetic, and an efficient hypnotic, producing a deep sleep of short duration, with more or less general anaesthesia and lowered reflex excitability. It is depressant to the heart, respiration and body temperature, but in medicinal doses does not leave any bad after-effects. Dose, ♏iv-v, repeated thrice at short intervals.

*Hypnal,—is a combination of Antipyrin and Chloral, occurring as tasteless and odorless rhombic crystals, soluble in 6 of water, and credited with simultaneous action as a hypnotic and analgesic. Dose, gr. xv-xxx in aqueous mixture with some alcohol, flavored with syrup of orange. It is said to cause no gastric disturbance. Although Chloral and Antipyrin are incompatible with each other, they form, when heated together, the above-described compound, which resembles both and yet differs from each.

Hyoscinae Hydrobromas, Hyoscine Hydrobromate,—(see ante, page 116)—is an efficient hypnotic, with the advantage of being tasteless, and having a very small dose, (gr. 1/100-1/60) so that it may be given in tea, coffee, etc. It is apt to affect the head afterwards, and does not soon lose its power by repetition. In large doses it is a dangerous respiratory depressant.

Cannabini Tannas, Cannabin Tannate,—(see ante, page 124),—is not more reliable than the Extract of Cannabis Indica, though devoid of the exciting qualities of the latter preparation. Dose, as a hypnotic, gr. ij-x, the average being gr. v. Fronmüller considers it a very useful hypnotic, powerful and not dangerous, not disturbing the secretions, nor leaving unpleasant aftereffects, if used in proper doses.

Physiological Action of Chloral. It is essentially a hypnotic, also a depressor of the cerebro-spinal centres, an antispasmodic, antiseptic, antiferment, counter-irritant, and prevents the coagulation of fibrin. It is more hypnotic than Chloroform, and less anaesthetic. Used hypodermically it is actively irritant, and produces extensive sloughing of the tissues.

The taste of Chloral is hot and pungent; if used in large doses or in strong solutions it may excite gastritis, with nausea and vomiting. After a brief period of stimulation it depresses the heart and arterial tension, diminishes oxidation, and lowers the body temperature. On the brain it has a selective action; by inducing cerebral anaemia it produces a deep sopor, very like normal sleep, from which the patient may be awakened but immediately falls asleep again, and is not followed by headache or depression. In some persons instead of sleep it causes headache, insomnia and delirious excitement. It is not an anodyne, as it does not affect the conductivity of the sensory nerves, and does not interrupt the transmission of pain, but by overwhelming the centres prevents the consciousness of pain, and is, therefore, only indirectly an anaesthetic. A Large Dose produces profound narcotism, abolishment of the reflexes and of sensibility, and complete muscular relaxation, with a great fall of temperature. Death may result in the chloral sleep, from paralysis of the cardiac motor ganglia and the respiratory centre, or by sudden failure of the heart in cases of fatty degeneration, or in old drunkards.

The Chloral Habit. Chloralism is a state of marked anaemia, its subjects presenting a weak, irritable, often irregular heart, deranged liver function, jaundice, bileless stools, perhaps purpura and sloughing of a finger, from decreased blood supply. Its votaries are on the border of insanity, excitable, uncontrollable in speech and action, talking in a silly manner and very volubly. Many cases of insanity result from the chloral habit.

Action of Chloral on the Blood. It diffuses rapidly into the blood, which, being an alkaline fluid, partially decomposes it, setting Chloroform free (?). It crenates the red corpuscles, and in large quantities destroys the leucocytes. It increases the fluidity of the blood, producing an anaemic condition. It is excreted by the kidneys, partly unchanged, but chiefly as Uro-chloralic Acid, producing some diuresis ;—also by the skin, causing various eruptions if long used.

Toxicology of Chloral. Atropine antagonizes its cardiac, respiratory and spinal depression, and should be given in small doses, frequently repeated, until its effects are apparent. Morphine given with chloral prevents the tendency to cardiac failure, while synergistic to its hypnotism. Chloral is the antagonist to Strychnine, opposing the spinal action of that drug, but the reverse is only true to a limited extent. Chloral and Atropine, though antagonistic in their actions upon the spinal cord, both produce motor paralysis,—the former by paralyzing the cord, the latter by paralyzing the motor nerves.

Therapeutics. Chloral is of great value as an hypnotic and antispasmodic, but must be cautiously used, if at all, in persons with weak or fatty hearts, atheromatous vessels, or advanced pulmonary disease. In combination with Potassium Bromide it is much used in asylum practice, and much abused; both drugs are cardiac poisons. It should never be given internally to relieve pain, but it is highly serviceable in—

Neuralgia,—if triturated with Camphor and applied locally.
Sea-sickness,—gr. v two or three times a day, generally very efficient.
Cholera in the algid stage, and in violent cases of cholera morbus,—gr. xv hypodermically every hour, of extraordinary efficacy.
Fevers, when high temperature, excitement, restlessness, and sthenic condition,—Chloral lowers the temperature, prevents the coagulation of fibrin, and is frequently of great utility.
Diphtheria,—Chloral in the first stage, but not if weak heart.
Obstetrics,—it is used to alleviate suffering, to relax the os uteri, to palliate puerperal convulsions, and to relieve after-pains.
Delirium Tremens,—Chloral is much used and is highly efficient. It produces the best sleep in this condition, but is dangerous to old drunkards with damaged hearts.
Tetanus,—the best treatment is by Chloral and Potassium Bromide.
Cancers and Ulcers,—a 25 per cent. solution locally, as an antiseptic and anodyne application.
Tic-douloureux,—Croton-chloral is an efficient palliative, given in 5-grain doses every half hour, up to gr. xxx.
Epilepsy,—for nocturnal attacks give Chloral in full dose, at bedtime.
Strychnine Poisoning,—Chloral is the antagonist par excellence.

A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.