The effect of different types of anesthesia on digitalis toxicity

Abstract

This investigation was undertaken in order to determine whether or not the type of anesthetic agent used modified the cardiotoxicity of either ouabain or acetylstrophanthidin. Ouabain toxicity was greater in animals anesthetized with chloralose and urethane than it was in animals anesthetized with pentobarbital. The toxicity of acetylstrophanthidin was the same under both types of anesthesia. It is suggested that these results can be explained by an interplay between differences in the pharmacological actions of the digitaloid substances studied and differences in the pharmacological actions of the anesthetics under question. The results of this study are significant for two reasons. They reinforce the importance of carefully choosing an anesthetic agent(s). All anesthetics do not produce identical pharmacological actions. Drugs that produce anesthesia can modify an animal's response to other drugs. There is a need for more information on the interaction between anesthetics and other drugs. This has clinical as well as experimental applicability. The differences between anesthetic agents with regard to interactions with catecholamines have been long recognized. 26,27 However, there appears to be little information on such differences between anesthetics with regard to other drugs. This study also points out the need for further study of the specific pharmacological actions of different digitaloid substances. It appears as though different cardenolides may have different potentials for increasing sympathetic activity. With further study, other differences may be found. The existence of differences in the pharmacological actions of different cardiac glycosides should increase the chances of finding a therapeutically useful cardioactive steroid that produces less toxicity than the agents that are currently in use. For example, the finding of a difference between digitaloid substances in ability to increase sympathetic outflow would improve the possibility of the development of a cardiotonic digitaloid substance that has little ability to increase sympathetic outflow. The new compound should have less potential for producing cardiac arrhythmias. Such a substance might be expected to be very useful clinically because the margin of safety should be larger than that of a similar compound that produces a significant increase in sympathetic outflow in addition to its direct positive inotropic effects.