[The pharmacology of a new cardiosteroid, a partially synthetic derivative of the aglycone hellebrigenin (acrihellin)].

3 beta,5,14-Trihydroxy-19-oxo-5 beta-bufa-20,22-dienolide 3-(3-methylcrotonate) (acrihellin, D 12 316) is according to chemical structure and pharmacological effects a semisynthetic compound of the aglycon hellebrigenin. It is characterized as a cardiosteroid. In isolated organ (Langendorff heart) the positive inotropic effect proved to be stronger in comparison to digoxin. Also in dogs and cats acrihellin increases the contractile force of the myocardium; especially in failing canine heart, it increases the force of contraction (strain-gauge) and velocity of pressure rise (dp/dt max). In classical glycoside test on cat (Hatcher's dose) acrihellin is more effective than digoxin and methyldigoxin on weight basis, equivalent on a molar basis. The therapeutical index of acrihellin is like that of methyldigoxin. In cats and dogs, the compound is absorbed rapidly and almost completely, especially when administered intraduodenally. Herein it is comparable to methyldigoxin, better than digoxin. In cats acrihellin shows a decay rate of 26%. In all investigations performed in order to study central nervous effects after single administration of therapeutical doses no central side-effects could be detected in contrast to methyldigoxin.