Cocaine, a Substitute for Chloroform: Cocaine is an alkaloid extracted from the leaves of the Erythroxylon Coca, which grows as a kind of shrub in Bolivia and Peru.
The hydrochlorate of cocaine is the preparation mostly used, as it is more soluble in water.
Cocaine is equal in its effects to chloroform in many operations where the parts to be removed are not very deep-seated; besides, its use is much more economical, as not only is the drug itself of less expense, but when operating it is not necessary to have a separate attendant to administer it, as is the case when chloroform is given. Then it is much more easily given (by a hypodermic syringe), and the dog does not resist it at all; whereas, chloroform is resisted by the patient with all its strength. In some cases three or four assistants are required to hold a big dog whilst it is being administered, and I have known some dogs to struggle so violently against taking chloroform that one has been obliged to discontinue giving it, for to have persevered would have endangered the dog’s life. This alone is sufficient reason to make cocaine a more favourable anæsthetic than chloroform.
Then as to the danger, there is no comparison between the two. I have only once had any bad results from the use of cocaine; but with chloroform, sometimes, in spite of every care and precaution, the dog will, when under its influence, suddenly collapse. Besides, when a dog, in a case such as I have just described, struggles very much against receiving the chloroform, it takes longer to get him under the influence of the drug than one taking it quietly; and then, often as a consequence, the dog at last becomes exhausted, and if the chloroform is persevered with, it takes too strong effect—the heart’s action becomes weak, the breathing heavy, and collapse may occur—the result is, one is obliged to leave off the operation to administer restoratives to save the patient’s life.
In many operations, as the excising of tumours (even large ones, weighing six or seven pounds), removing thorns from the eye, sewing and dressing painful wounds, cocaine is equal to chloroform in its effects, for it completely deadens for a time the parts to which it is applied, though the animal retains complete consciousness.
It is particularly valuable when removing mammary growths, so frequently seen in bitches. On many occasions I have removed a growth of this kind weighing, in some instances, seven to eight pounds, without subjecting the dog to the least pain; and I may here remark that the application of cocaine does not in any way retard the healing process.
Cocaine for most purposes is best used dissolved in water; the quantity of the solution required depends upon the size of the growth that is going to be removed. For small tumours, say the size of a large walnut, a four per cent. solution is generally sufficient. Of this about twelve minims should be injected under the skin, say three drops at each corner of the growth, then in the course of about ten minutes the parts will be completely insensible to pain and ready for operation. The same strength of solution is also strong enough for eye operations, including the removal of growths on the haw. In such cases the solution of cocaine must be dropped into the eye. About five or six drops is all that is required; one drop to be placed into the eye every minute until the quantity required is given, then wait ten minutes for the cocaine to take effect. In cases of operation for inverted eyelid, the use of cocaine is invaluable.
When removing large growths, a five per cent. solution is necessary, giving the same quantity—about twelve minims—injecting one minim just under the skin all around the tumour, and where the skin is going to be cut.
There are other local anæsthetics as eucaine, which is said to be safer than cocaine; but in my opinion it is not nearly so good, at any rate with dogs, and the latter is perfectly safe when used in proper doses.