RESIBUFOGENIN OBTAINED FROM TOAD VENOM AND ITS PHARMACOLOGICAL AND TOXICOLOGICAL EFFECTS

Resibufogenin (RBG) is separated and extracted from Ch'an su, which is obtained from toad skin gland venom. Ch'an su is a famous traditional Chinese medicine and is used extensively in clinical practice in Chin a. RBG is a cardiac glycoside and its chemical structure is similar to digitoxigenin. RBG has exhibited three significant efficient pharmaco logical actions: 1) as digitalis, RBG is a cardiotonic agent possessin g positive inotropic effects; 2) RBG produces an increase in mean syst emic arterial blood pressure: and 3) the specific pharmacological effe ct of RBG is an excitatory action on respiration. On the other hand, R BG has toxicity similar to digital is, especially its arrhythmogenic e ffects, such as inducing delayed after depolarizations and triggered a rrhythmias. Because of this reason, a few recent clinical reports have described digitalis toxicity caused by Ch'an su or toad venom. Howeve r, the pharmacological characteristics of RBG and its toxicity are not yet well known clinically. The purpose of this article is to impartia lly review the pharmacology and toxicity of RBG.