Coca. The leaves of Erythroxylon coca Lamarck (Nat. Ord. Lineae).


Extractum Cocae Fluidum. — Fluid extract of coca. Dose, 3 ss— 3 ij.


The effects of coca depend on the presence of a peculiar alkaloid—cocaine. It contains also an aromatic oil which gives it the special aroma and taste, and it possesses considerable astringency, due to the presence of a tannic acid. The odor, taste, and appearance of the infusion are comparable to those of tea. Cocaine has decided basic properties, and combines with acids to form salts. It crystallizes in prisms in the smaller rhombic system (Huse-mann), which, when pure, are transparent and colorless. It is very slightly soluble in water and in alcohol, but dissolves freely in ether. It has a bitter taste, and the salts are more bitter than the alkaloid itself.

Cocainae Hydrochloras

Cocaine hydrochlorate. Colorless, transparent crystals, or a white crystalline powder, without odor, slightly bitter taste, and producing on the tongue a tingling sensation, followed by numbness of some minutes' duration. Soluble at 59° Fahr. (15° C.) in 0·48 part of water and in 3·5 parts of alcohol.

Tropacocaine (benzoylpseudotropein) is an alkaloid of the smallleaved coca of Java. This was first extracted from the plant by Gie-sel, and it was made synthetically by Liebermann, who proved its identity with pseudotropein of hyoscyamus.

Physiological Actions

The historical notes of Sir R. Christi-son show that the peculiar properties of cuca-leaves have long been known to the inhabitants of Peru. The leaves have a strong, tea-like odor, and the infusion resembles ordinary tea in taste. The volatile oil and the active principle are readily diffusible, and enter the blood with facility. A momentary depression of the pulse and diminution of the blood-pressure take place, but these effects are quickly overcome, and a considerable increase in the action of the heart and of the blood-pressure follows (Ott). A feeling of contentment and of well-being takes possession of the mind, the sense of fatigue is removed, drowsiness is experienced for a brief period, but it is soon succeeded by wakefulness and increased mental activity. It has long been known to the mountaineers of the Peruvian Andes that chewing cuca-leaves increases the respiratory power, and removes, or lessens, the sense of fatigue. The celebrated pedestrian, Weston, having learned this fact, was detected in the use of cuca during one of his extraordinary feats in London (Thompson).

Although erythroxylon (coca or cuca) had been the subject of investigation and its power to suspend the functions of the sensory nervous system recognized, the character of its local action was not suspected. It was reserved for Dr. Koller, of Vienna, to discover its analgesic effects when applied directly to the mucous membrane, and this great fact he demonstrated before the Ophthalmological Congress at Heidelberg. It happened that the distinguished ophthalmologist of New York, Prof. Dr. Noyes, was in attendance on the Congress, and he sent to the New York "Medical Record" a letter giving the facts of the discovery, and this proved to be the first statement in the English language of Koller's demonstration. As the possibilities of the future utility of cocaine as a local anaesthetic was then recognized, it created a profound impression, and in an incredibly short time this remarkable discovery became the common interest and the common possession. Everywhere cocaine was investigated by physiological and clinical methods, and the results confirmed the statements of Koller. By no one on this side of the ocean was the investigation of the properties and powers of cocaine, more especially from the standpoint of the ophthalmologist, more carefully conducted than by Knapp, of New York, who confirmed the results attained by Roller. Before the Congress of Ophthalmologists Roller exhibited the effect of a four-per-cent solution applied to the conjunctiva—such a degree of anaesthesia being induced by it that this delicate membrane bore cutting, pinching, and tearing without any manifestation of pain and without exciting reflex action. It was also shown that the local action of cocaine included a condition of anaemia of the parts due to an active contraction of the arterioles. Only the mucous membrane is rendered anaesthetic. The skin is not penetrated unless an abrasion or some punctures permit the solution to pass through.

It was early observed that idiosyncrasy influences greatly the effects of cocaine. A few drops instilled into the eye and through the vessels of the nares entering the circulation have caused sudden and severe depression of the vital powers, great weakness of the heart's action, slow and shallow respiration, and convulsive jerkings of the muscles. Similar and more severe symptoms have accompanied the hypodermatic injection of a small dose (an eighth of a grain), and death has ensued suddenly from heart-failure in not a few instances when moderate doses have been administered in this way.

The character of the action of cocaine is much influenced also by the amount administered, and the several stages of its action differ because the immediate and primary effect is necessarily opposed to the condition of reaction which seeks to restore the normal. When a sufficiently active dose is given, the first effect is stimulation; the heartbeats are accelerated; the respiration becomes more frequent; the reflexes respond to a distant irritation more promptly; the mind experiences a grateful sense of well-being and of activity, and ideation is ready, acute, and comprehensive.

The stage of excitement continues for an hour or two, and is succeeded by depression, which is at the same time physical, mental, and moral. The pulse may continue quick, but its force declines, and some irregularity of the rhythm may occur; the skin grows moist or profuse sweating comes on; the body temperature declines a little, possibly; the appetite is lost, and nausea and vomiting increase the feelings of physical wretchedness and moral distress. These are the conditions which impair nutrition. Observations made on those unfortunates addicted to the use of morphine and cocaine have proved misleading. The decline in the weight of the body is for the most part due to the gastro-intestinal derangement and to the complete anorexia which is a result of the withdrawal of the morphine. No doubt cocaine contributes to the wasting to some extent. Although cocaine is not actively toxic, and may be taken in enormous doses, some persons are highly susceptible to its action, and are profoundly depressed by a minute quantity. On the one hand, we find that Dr. Hammond, who reports taking eighteen grains at a single dose, has experienced only disturbed sleep and severe headache as a consequence; on the other hand, a susceptible woman, who is made faint, nauseated, and seriously depressed by the minute quantity that has passed into-the nares from an instillation into the eye.

In the smaller medicinal doses (1/8 to 1/4 grain) cocaine stimulates the nerve-functions, gives clearness and power to the tones of the voice, heightens the reflexes, and raises the arterial tension. Large doses act briefly in the stimulating way above described, but the depression stage quickly succeeds, then the mental activity declines, memory is impaired, and a sense of weariness comes on. During this period there is more or less sweating, sometimes profuse, and a tingling and pricking sensation accompany it.

Cocaine pursues a certain order in its action on the brain and nervous system: first the hemispheres, then the lower motor and co-ordinating centers and the reflex centers, including respiration and also the vaso-motor center. The sensory paralysis includes the posterior columns; but it is held by the principal authorities that it begins in the peripheral nerves, and thence extends to the sensory tract in the spinal cord. Cocaine has a distinctly convulsant action in animals, as has been experimentally shown by many observers. These convulsions are clonic in character. Similar results occur in man from large doses, and have been especially observed in the subjects of its habitual use, when suddenly acted on by massive doses. The convulsive movements are accompanied by irregular action of the heart, by sighing and shallow respiration, and by hallucinations of vision and hearing.

Cocaine first stimulates and afterward paralyzes the pneumogastric nerve, and the respiration is first increased and afterward paralyzed, failure of respiration being the mode of dying.

The utility of cocaine was first demonstrated in ophthalmological practice. The manner of its action on the eye has been carefully worked out as a basis for its therapeutical applications. When instilled into the eye, anaesthesia is first induced in the conjunctiva and cornea, and this effect may be accomplished by a solution having the strength of 2 to 100; but stronger solutions (5 to 100) act more quickly and efficiently. When the deeper parts of the eye are to be acted on, the stronger solutions are made use of, and the contact must be sufficiently prolonged. Wounds of the eyes and incisions made are utilized to secure the diffusion of the anaesthetic to the deeper parts of the organ. A simple congestion of the conjunctiva does not hinder the effects of cocaine; but chronic changes in the structures of the organ have a retarding influence. Some dilatation of the pupil begins in about fifteen minutes after an instillation, but the pupil remains sensitive to light (Koller). Accommodation is somewhat affected, but not sufficiently so to be an interference. The mydriasis reaches its maximum in about an hour, and subsides in three or four hours afterward.

Cocaine is eliminated by the kidneys and may be detected in the urine. The excretion takes place in a short time, in a few hours.

Coca Therapy

The preparations of coca, especially the wine, are much employed as stomachic tonics. The consumption of wine of coca (a solution of cocaine in wine) must be enormous, for numerous preparations are on the market. They are advertised in the most lavish manner, and so freely dispensed to physicians in the form of trial specimens that only large sales with immense profits can justify the expenditure. The author has observed that clergymen, and men with scruples and high moral character, take this wine freely, and not without a devout appreciation of its grateful action in time of need.

To illustrate: a clergyman of character, attainments, and rhetorical skill, informed me that he always took a small wine-glassful of the wine of coca before his Sunday morning service. He had found that it banished fatigue, gave a resonant tone to his voice, and freed his intellect from the trammels of a written discourse, and gave scope and power to his sermon. Those who at first experienced this grateful addition to their resources came after a time to that melancholy stage of its action when the dose taken must be larger, and consequently an increasing depression with its baleful associations continually succeeds to the shortening stage of agreeable excitation.

In various neuroses of the respiratory organs, asthma, whooping-cough, singultus, etc., there can be no doubt respecting its curative power, and small doses are more useful than large ones in these cases. The effects are more decided when the remedy is thrown under the skin, and a single dose may give more relief than weeks of other treatment. In the case of neurotic individuals with the irritable and impressionable nervous system characteristic of the type, cocaine, more especially when administered hypodermatically, has acted in a way to indicate serious danger. We have already pointed out how it is that such an idiosyncrasy may endanger, even take, life by sudden failure of respiration or of circulation.

The topical action of cocaine in hay-fever has proved to be a valuable expedient. The solution, four to ten per cent, in spray or applied by the brush to the whole surface of the nasal and faucial mucous membrane, lessens congestion and secretion, and prevents the passage to the respiratory center of the peripheral irritation. Better than with a solution the parts affected are easily acted on by the slow solution of a compressed pellet placed conveniently in the anterior nares behind the cartilages. Numerous reports have been made of the complete relief afforded by this mode of application.

Most remarkable have been the successes obtained by the local applications of cocaine to abate inflammation, to stop or to relieve pain. It must not be forgotten that swallowing during and immediately after local applications to the nares and fauces may cause systemic effects. Cases have occurred in which a small quantity thus entering the system has brought on the most alarming syncope. The small quantity escaping by the tear-duct into the nose, thence into the oesophagus, has also in a few instances caused faintness.

Cocaine is a remedy of the highest value in chorea. The author has repeatedly cured cases in which all the ordinary and some extraordinary remedies had been used in vain. The whole amount given daily has rarely exceeded one half a grain. Paralysis agitans, alcoholic tremors, and senile trembling, are more favorably affected by cocaine than by any other remedy. Large doses and frequent administration are unnecessary, and if carefully attended to the special influence of the remedy on consciousness need not be developed to a sufficient extent to form a habit.

Combined with atropine, cocaine becomes a valuable hypnotic; for example: Rx Cocainae hydrochlor., gr. xv; atropine sulphat., gr. ss. M., ft. pil. no. Ix. Sig.: One or two at bed-hour.

The enormous value of cocaine as a local anaesthetic in ophthalmology is fully conceded, and no less useful has it proved to facilitate manipulations and to render them painless in laryngological, genitourinary, obstetrical, and gynaecological and rectal surgery. It would be a labor of supererogation to enlarge on this topic. It has been successful in a remarkable degree in the treatment of vaginismus, pruritus, and cutaneous maladies in which itching is the most troublesome symptom. The solution used for these purposes should have a strength of five to ten per cent.