CHAPTER XV.USES OF COCAINE.
The curious property cocaine possesses of producing local anæsthesia was even noted by the discoverer of the alkaloid—Niemann, who, so far back as 1860, wrote: “It produces temporary insensibility on the part of the tongue with which it comes in contact” (Watts’s Dict.,1st Edition, i. 1059,ex“Ann. Ch. Pharm.” cxiv. 215). This interesting fact lay dormant until in 1884, Herr Koller, a medical student in Vienna, was led to test the local anæsthetic action of the hydrochlorate of the alkaloid, on account of the effect he had witnessed when cocaine in solution was pencilled upon the pharynx to render it less susceptible in laryngoscopic examination. A vial of the solution was given by Herr Koller to Dr. Brettauer, of Trieste, who, on Sept. 15th, 1884, demonstrated its properties at the meeting of the Ophthalmological Congress in Heidelberg. Several experiments were made with the two per cent. solution, which showed that when two drops of the liquid were placed upon the surface of the normal cornea, and the application repeated after an interval of ten minutes, at the end of ten minutes more, the sensibility of the cornea was so far diminished that it could be pressed with a probe; the cornea and the surface of the eyeball and eyelids adjoining could be rubbed; a speculum could be inserted and the lids widely separated, the conjunctiva could even be seized with fixation forceps, and the eye moved in various directions without causing the patient notable discomfort.
Besides rendering the superficial structures of the eye anæsthetic, it is a mydriatic, and produces paralysis of the accommodation, which passes off sooner than the dilatation of the pupil; this does not at longest last more than twelve hours. The sensitiveness of the iris is less affected than that of the surface of the eye. The great excellence of cocaine consists in the limitation of its action to the tissues to which it is applied. No doubt, other symptoms at a distance do result from the external application of the anæsthetic, but they are, for the most part, insignificant and free from dangerous consequences. In some measure cocaine may be compared with curare. The one agent paralyses the termination of the sensory nerves, whilst the other paralyses the termination of the motor nerves. Cocaine would seem to act in a manner the reverse of aconite. When applied to a mucous membrane, it has probably a constricting action on the vessels, produces a blanching of the part, and simultaneouslya deadening of the nervous excitability which passes into a complete state of anæsthesia; its effect, however, does not sink deeply into the adjacent tissues, nor does it last long. This surface application is sufficient to render painless the use of a caustic, the passage of catheters and lithotrites, or the performance of operations which do not involve the more deeply-seated tissues. Such operations as the opening of abscesses and buboes, the removal of small tumours, require the surface anæsthesia to be supplemented by two or more hypodermic injections, of a quarter of a grain in each, of the hydrochlorate in close contiguity to the part to be operated on. Injected hypodermically, the aqueous solutions of its salts deaden sensibility around the puncture, so that the deep prick of a pin is not felt—the surrounding part is reddened, but after thirty minutes it resumes its normal condition; injected locally, is more useful than morphine in relieving sciatica. Although solutions of it are little absorbed by the skin—even a chloroform solution is scarcely at all absorbed—yet the application of an ointment of the pure alkaloid, made with lard, or an oily solution of it, to a surface will remove the pain of inflammation, as in eczema or erysipelas, or the pain of facial neuralgia or shingles, and the irritation of urticaria or pruritus. Burns and scalds should first be brushed over with a 4 per cent. aqueous solution of the hydrochlorate, and the pure alkaloid combined with carron oil (Linimentum Calcis), petroleum cerate, or boric acid ointment, afterwards applied on cotton wool or lint. Combined with boric acid ointment, also, it may be used for fissured nipples, or for these and stings and bites of insects an aqueous solution may be applied. The irritability of inflamed mucous surfaces, as in hay-fever, influenza, coryza, bronchitis, spasmodic asthma, laryngitis, and pharyngitis, is much relieved by the spray of a watery solution of a cocaine salt. In obstetrics, its local application relieves the pain of the dilating os uteri, and diminishes the sensibility of the perinæum whilst being dilated in first labours; rents of the perinæum may be stitched up almost painlessly under its action, and under its influencemany minor gynæcological operations are much facilitated by the ability to insert needles and make small incisions without pain. The spasmodic and painful affections of the vagina, causing dyspareunia and vaginismus, may be minimised by vaginal injections of a quarter of a grain of cocaine in 1 per cent. oily solutions. In dentistry, it is useful in toothache; it deadens the sensibility of exposed pulp. The pure alkaloid is preferable to the salts for this purpose, because, being only slightly soluble in water, it is less liable to be washed away by the saliva. If a little be inserted in the cavity of a carious tooth and covered with a plug of mastic solution, all pain is obtunded for a considerable time. A strong solution in oil of cloves is also useful. In preparing the cavity, previous to filling, the sensitiveness of the dentine is more effectively treated by using a salt of cocaine—either the hydrochlorate or citrate; the latter has been recommended, as it can be formed into a pellet with the fingers and pressed into the cavity, but it is not so rich in true alkaloid as the hydrochlorate; yet, either of these is absorbed more quickly than the alkaloid itself, which, as before said, is more suitable for plugging a cavity for some length of time. Before using arsenical paste to destroy the nerve when exposed, if about a quarter of a grain of a cocaine salt be inserted into the cavity, after partially clearing, it will anæsthetize the pulp in about five minutes, and enable the operator thoroughly to open the cavity and expose the pulp directly to the action of the arsenical paste without pain to the patient. In extraction, if a dose be hypodermically injected into the gum on each side at the base of the tooth, after waiting about five minutes this may be done almost painlessly, and, if a 50 per cent. aqueous solution of the hydrochlorate be painted on the surrounding gum, the first pain of inserting the forceps is annulled. The eye, ear, throat, mouth, tongue, pharynx, nose, larynx, trachea, urethra, vagina, os uteri, anus, rectum, and, in fact, the whole mucous membrane, as well as cut surfaces and open sores, are affected by it, but the true skin is less so.
Solutions of hydrochlorate of cocaine have beenemployed topically in excision of the tonsils, cauterizing the turbinated tissue of the nose, painting chancres previous to the application of nitric acid or other caustics, opening abscesses, removing polypi, and many cases of iridectomy and operation for cataract, squint, and the removal of foreign bodies from the eye. For the eye an aqueous solution of the hydrochlorate of cocaine of mostly 2, but sometimes 4, per cent. is used, and for other purposes from 4 to 20 or even 50 per cent.; of the weaker solutions it is necessary to repeat the application three to five times, at intervals of three to five minutes. No operation should be commenced within at least ten minutes of the first application. Injurious effects, either local or constitutional, rarely follow its use. Its action commences in three minutes, increases from ten to twenty minutes, and mostly disappears within half an hour. The anæsthesia may be prolonged by applying an Esmarch’s bandage round the site of injection.
Uses of Cocaine, and cautions on its employment; a summary of the experiences of fifty-two surgeons in the United States.In minor surgery—is of value in all operations where circulation can be temporarily arrested in order to prevent undue absorption. A fresh solution should be employed, of strength not exceeding 4 per cent. Caution is required when the circulation cannot be controlled. Is of little use as a local anæsthetic in anal work, such as fistula. In genito-urinary surgery must be used with care, as it is in this class of cases that untoward effects have been most marked; the solution should not remain in contact with mucous surface more than a few moments. In gynæcological work it is of limited service, as general anæsthesia is mostly to be preferred. For ophthalmic surgery, Cocaine is the anæstheticpar excellence; in no other department of surgery is its use so widespread and its application so entirely satisfactory. It is suitable for all operations on the eyeball, except iridectomy for acute glaucoma, and enucleation; as it causes dryness of the epithelium it should not be used long prior to operation. Is of great value in nasal, aural, and throat operations.—Th. Gaz. Aug. 1891, 518.
Chloroform and Cocaine Anæsthesia(combined).—Chloroform is given, 1 to 3 drachms, with an Esmarch’s mask, and from ½ to ¾ grain of cocaine, in 3 to 5 per cent. solution, injected into the part. Less chloroform suffices, vomiting is rare, and depression on waking slighter than chloroform alone produces.—L ii./88,220; B.M.J. ii/88,903. Th. Gaz. Sept. 1888, 630; Oct. 686; Dec. 849.
Equal parts of an 8 per cent. solution and liquor atropinæ sulphatis form an effective remedy for all painful and inflamed conditions of the eye; and half a grain of pilocarpine nitrate, added to 1 drachm of a 4 per cent. solution, produces anæsthesia without in the least disturbing the accommodation.—Whitla.
As regards the toxic properties of cocaine, its effects appear to be mild and not cumulative. It causes cessation of respiration,—small doses have an exhilarating effect on the nerve-centres and other parts of the nervous system. In a case of attempted suicide by an apothecary, a dose of 1.5 grammes (23 grains) seemed to have no seriously injurious effect.—Varge’s “Zeitschr.” v.f. 11, 5, p. 222, 1863.
A writer in theBritish and Colonial Druggist, Feb., 1885, p. 36, thus describes the effect of a full dose:—
“Inasmuch as the writer—whose nervous system is of an almost unfortunate degree of sensitiveness—has taken doses of the hydrochlorate, equivalent, in the aggregate, to no less than 32 grains of cocaine itself within the space of three hours, without (as the present lines sufficiently prove) a fatal result following, this remarkable body cannot fairly be classed among the poisonous alkaloids. Among the chief symptoms induced were increased cerebral activity mounting at intervals into the region of delirium, the latter tendency always subservient to a powerful effort of the will. This continued for five hours, the heart action and breathing being meanwhile slightly increased, but not to any painful extent. At first the muscular powers appeared to be enhanced, heavier weights being lifted without undue stress than is ordinarily the case, while the reflective faculties—as instanced by ability to read andform conclusions upon novel scientific matter—seemed stimulated. An hour after the entire quantity named had been taken, the sensibility of the limbs to external influences—which had gradually diminished from the first—became materially lowered, and neither pinches, pricks, nor slight burns with a heated wire could be felt upon the fleshy portions of the arms or legs. The trunk, however, never lost its sensibility to pain in any marked degree.“Slight convulsive movements and a sensation of bodily torpor succeeded, giving way about the eighth hour to considerable somnolency. No special desire, or distaste, for food was noticeable, but sleep overcame all other symptoms between ten and eleven hours from the commencement, and continued for thirteen hours afterwards; a slight feeling of dizziness was experienced on waking, but this gradually wore off, and had entirely disappeared twenty-four hours later.”
“Inasmuch as the writer—whose nervous system is of an almost unfortunate degree of sensitiveness—has taken doses of the hydrochlorate, equivalent, in the aggregate, to no less than 32 grains of cocaine itself within the space of three hours, without (as the present lines sufficiently prove) a fatal result following, this remarkable body cannot fairly be classed among the poisonous alkaloids. Among the chief symptoms induced were increased cerebral activity mounting at intervals into the region of delirium, the latter tendency always subservient to a powerful effort of the will. This continued for five hours, the heart action and breathing being meanwhile slightly increased, but not to any painful extent. At first the muscular powers appeared to be enhanced, heavier weights being lifted without undue stress than is ordinarily the case, while the reflective faculties—as instanced by ability to read andform conclusions upon novel scientific matter—seemed stimulated. An hour after the entire quantity named had been taken, the sensibility of the limbs to external influences—which had gradually diminished from the first—became materially lowered, and neither pinches, pricks, nor slight burns with a heated wire could be felt upon the fleshy portions of the arms or legs. The trunk, however, never lost its sensibility to pain in any marked degree.
“Slight convulsive movements and a sensation of bodily torpor succeeded, giving way about the eighth hour to considerable somnolency. No special desire, or distaste, for food was noticeable, but sleep overcame all other symptoms between ten and eleven hours from the commencement, and continued for thirteen hours afterwards; a slight feeling of dizziness was experienced on waking, but this gradually wore off, and had entirely disappeared twenty-four hours later.”
By physiologists, it had been supposed that cocaine would have properties allied to, if not identical with, caffeine, theme, or theobromine, in the manner that these themselves are allied. But, chemically, cocaine is quite distinct; it is much less soluble in water than caffeine; it is a strong base, which caffeine is not, and its chemical constitution and derivatives are quite distinct from those of caffeine. As a medicine, the coca leaf has been more used in France and America than in England.
Opinions are at present divided as to whether the anæsthesia produced by Cocaine is the result of vasomotor disturbance—the small vessels are caused to contract by its application, and the nervous filaments are doubtless anæmic—or whether Cocaine acts directly as a paralyser on the nervous endings, whether of sensibility, or touch, or of special sense, since it removes the power of taste and smell, as well as the perception of touch and pain. When Cocaine is administered in such a dose and manner as to affect the whole system, the brain seems to become excited, the heart stimulated, and blood and pressure increased. Poisonous doses kill by asphyxia, the breathing becoming arrested andthe heart failing in diastole; but this has not yet been observed in man, the dose necessary to produce this effect being very large; 20 grains have been taken without very serious result. It diminishes all the secretions, and, although the intestinal movements are slightly stimulated at first, larger doses or continued use cause sluggish action, dyspepsia, and constipation. Tissue change is lessened, and the amount of urea is similarly diminished; the temperature seems to be somewhat higher than normal; albuminuria has been found to follow its use, and sugar has been found in the urine. The kidneys are probably the special means of its elimination. With regard to its action on muscular fibre nothing is known, observers being completely at variance in their opinions.—Buxton, in Ringer’s “Therapeutics,” 12th edition.
“Brown-Séquard regards the effect as a new sample of inhibitory action, his experiments convincing him that Cocaine acts through the medium of the peripheral nerves on the nervous centres, which react in bringing about inhibition of sensibility. The phenomena which result from the injection of Cocaine at the level of the larynx, he finds to be the same as those which are consecutive to the application of a jet of carbonic acid on the mucous membrane of that organ. Two minutes after the injection there is a generalised anæsthesia and an analgesia of the different wounds made on the body of the animal. The cutaneous anæsthesia lasts only a few minutes, but the analgesia of the wounds persists even till the following day. If fresh wounds are made, these, far from being analgesic, become, on the contrary, hyperalgesic. That which proved that Cocaine acts on the nervous centres, and particularly on the cerebellum, is that injections of this substance produced sometimes a rolling motion to the side opposite to the injection, and at others a turning motion. Evidence of the inhibitory action is offered by another of Brown-Séquard’s experiments: when the dose of Cocaine injected was large enough to produce convulsions, it was sufficient to pull or forcibly flex the toes to immediately stop the convulsions. In animals which died under these conditions the temperatureof the body after death was as high as 44°·4 C, or 111°·6 F.”—Brown-Séquard in Prosser James’ “Guide to New B.P.”
“Brown-Séquard regards the effect as a new sample of inhibitory action, his experiments convincing him that Cocaine acts through the medium of the peripheral nerves on the nervous centres, which react in bringing about inhibition of sensibility. The phenomena which result from the injection of Cocaine at the level of the larynx, he finds to be the same as those which are consecutive to the application of a jet of carbonic acid on the mucous membrane of that organ. Two minutes after the injection there is a generalised anæsthesia and an analgesia of the different wounds made on the body of the animal. The cutaneous anæsthesia lasts only a few minutes, but the analgesia of the wounds persists even till the following day. If fresh wounds are made, these, far from being analgesic, become, on the contrary, hyperalgesic. That which proved that Cocaine acts on the nervous centres, and particularly on the cerebellum, is that injections of this substance produced sometimes a rolling motion to the side opposite to the injection, and at others a turning motion. Evidence of the inhibitory action is offered by another of Brown-Séquard’s experiments: when the dose of Cocaine injected was large enough to produce convulsions, it was sufficient to pull or forcibly flex the toes to immediately stop the convulsions. In animals which died under these conditions the temperatureof the body after death was as high as 44°·4 C, or 111°·6 F.”—Brown-Séquard in Prosser James’ “Guide to New B.P.”
In Vienna, Cocaine has been recommended for use internally in cases of great exhaustion, such as loss of blood, sunstroke, or diarrhœa, also by mouth or hypodermically as a cure for morphine and alcohol craving. Morphine and Cocaine appear to be mutually antagonistic. Cocaine has been used in some cases of melancholia and insomnia; it also possesses aphrodisiac properties. It was likewise found to lessen the desire for sleep and feeling of hunger, and to be a stimulant which quickly increases and sustains, in a harmless manner, the physical powers of the body, such as are required in long marches, mountain ascents, &c., in dose of ¾ to 1½ grains.
Cocaine is a stomachic, useful after excess either in eating or drinking, in distaste for food, in sea-sickness and vomiting of pregnancy, or from other causes; it also improves the condition of the stomach in atonic indigestion and nervous affections of this organ, as well as in phthisis and cachectic cases, especially those arising from the use of mercury.