The duration of action of some cardiac glycosides and aglycones in the guinea-pig.

A method is described for determining the duration of action of cardiac glycosides and aglycones in the guinea-pig. It is based on their property of potentiating the cardiac response to adenosine. The method is particularly suitable for those drugs with a short duration of action, whereas previous methods are more suitable for those drugs with longer durations of action. The duration of action of one-fifth of the lethal dose has been found for: digoxigenin, lanatoside C, ouabain, digitoxigenin-3-one, digitoxin, 3-acetyldigitoxigenin, digoxin, digitoxigenin, lanatoside A; these drugs are arranged in order of increasing duration of action. The possible relationship between the elimination of these drugs and their duration of action can provide an estimate of their rates of elimination.