A COMPARATIVE STUDY OF THE LOCAL ANESTHETIC PROPERTIES OF P-AMINO BENZOYL DI-ISO-PROPYL AMINO ETHANOL HYDROCHLORIDE ("ISOCAINE"), COCAINE, PROCAINE AND BUTYN

¹ From the Pharmacological Laboratory of the University of Wisconsin

"Isocaine" or p-amino benzoyl di-iso-propyl amino ethanol hydrochloride promises to be of value for anesthesia of intact mucous membranes. It is practically equally as efficient as cocaine in anesthetizing the cornea and is only about three-tenths as toxic. For paralysis of sensory nerve trunks it is less valuable than procaine because it is twice as toxic and only equally as efficient in blocking sensation.

Butyn probably has no advantage over cocaine for anesthesia of the intact mucous membrane. It is more efficient than cocaine in anesthetizing the cornea but this advantage is overcome by its greater toxicity. For paralysis of sensory nerve trunks butyn is only one half as efficient as procaine and is about ten times as toxic.

Data are presented in regard to the differences in susceptibility of various types of animals to local anesthetics. The minimum lethal doses obtained for rats are a great deal higher than those for mice, rabbits and cats. Likewise, cats are by far the most susceptible of the four types to all the drugs. Mice and rabbits are intermediate between the two, the former being less susceptible than the latter. The relative toxicity of the four drugs investigated is approximately the same for mice, rats or rabbits. With cats, however, the toxicity of cocaine increases beyond that of the other compounds so that the relative toxicity of the other compounds becomes less.