This section is from the "A Practical Treatise On Materia Medica And Therapeutics" book, by Roberts Bartholow. Also available from Amazon: A Practical Treatise On Materia Medica And Therapeutics
Attention was called to the actions of atropine and cocaine at the time an attempt was made to float into prominence a fraudulent remedy composed of a mixture of the two. As the actions of the supposed new remedy were studied by some who are eminently qualified for the task, and as new facts were thus ascertained, it is clear that sufficient merit was found in the combination to justify some notice of it here in this form.
A two-per-cent solution of the compound applied to the conjunctiva, or mucous membrane of any part, induces anaesthesia in about five minutes. If applied to the conjunctiva, the anaesthesia is accompanied by a mydriasis of the maximum extent, the dilatation beginning in ten to fifteen minutes, and reaching its greatest extent in twenty minutes, but remaining in that condition for twelve to twenty-four hours, and not entirely disappearing for three days. The accommodative apparatus is acted on quite vigorously, becomes paretic in ten to fifteen minutes, and completely paralyzed within a half-hour. The anaesthetic effect is induced when the solution is applied to the mucous membrane in any situation—the fauces, nares, urethra, etc. In some subjects such a degree of susceptibility to its action exists that the absorption of a minute quantity causes nausea, pallor, vertigo, and rapid action of the heart. In this respect, as in the anaesthetic action, it more resembles cocaine: in its mydriatic action and paralyzing effect on the accommodative apparatus more atropine. In the rapidity of the action on the pupil, in the degree of dilatation, and in the persistency of the mydriatic effects, it has more the action of atropine, but is more powerful and also more enduring.
Injected subcutaneously, very soon convulsions of a tetanic character are produced; trembling precedes the tonic spasms, and occurs also between them, while paresis, quickly passing into paralysis, results from the exhaustion of over-stimulation. In respect to the behavior of the tetanic convulsions, they more resemble those of picrotoxin than of strychnine.
When the mixture was first brought forward it was asserted that it affected cutaneous sensibility in the same way that it does that of the mucous membranes. Knapp was unable to verify this observation, and such a claim has not been made since.
The therapeutical applications of the combination can be deduced from the physiological actions. Thus far the course of the investigations has been limited to the uses of the new mixture in ophthalmic practice; but indications are thus furnished to guide its applications in diseases in general.
The conclusions of Knapp, based on Dr. Claiborne's and his own observations, are as follows:
In cases of iritis, the combination of cocaine and atropine is superior to cocaine alone, and should also be preferred to atropine alone when pain is suffered, and when a tendency to glaucoma exists. On the other hand, when the mydriasis is an objection—as in the case of most of the operations on the eye—cocaine should be preferred. When paralysis of the accommodative apparatus is desirable, the compound acts as efficiently as atropine, and is preferable, because its effect is shorter in duration.
Small doses, rapidly absorbed, may cause, as does cocaine, some general disturbance, which consists in sudden pallor, cold sweats, vertigo, stupor, faintness, etc., and large doses, approaching lethal in strength, bring on tetanic spasms, trembling, rapid action of the heart, and failure of respiration.
Inducing complete anaesthesia of the mucous membrane at any point, surgical procedures of all kinds may be carried on without any sensation of uneasiness. In all the morbid states in which cocaine has hitherto been used alone, the combination may be substituted, unless the dilatation of the pupil constitute an objection.
It has long been known that chloral has the power to liquefy various agents, as camphor, urethan, and others. The combination of chloral and urethan being effected, cocaine will dissolve in it to any desirable extent. Thus: Rx Chloral hyd., urethan, āā 3 ij. M. Solve. To the solution add cocain. hydrochlorat., gr. ij vel gr. iv. M. Dose, τη x—τη xx vel 3 ss. As this will mix with water without separating, it becomes a convenient and powerful anodyne and anaesthetic.
Under the name Uralia this preparation has been brought forward recently as new, and extravagant praise given it as an anodyne.
Benzoyl pseudotropeine. A substitute for cocaine. Locally applied in 3-per-cent solution, in a 6-percent solution of common salt. It is far less toxic than cocaine, and the anaesthesia caused by it comes on more rapidly and lasts longer. In ophthalmic work it is preferred to cocaine because it does not cause hyperaemia, and does not dilate the pupil. It may be used in Schleich's method as a substitute for cocaine, and, indeed, supplant the latter in all cases.