THE PHARMACOLOGICAL AND TOXIC ACTION OF DIGOXIN

¹ The Wellcome Physiological Research Laboratories, Langley Court, Beckenham, Kent

Digoxin, a glycoside isolated from the leaves of digitalis lanata, possesses the general characteristics of the digitalis group of cardiac glycosides.

Its action on the blood pressure and the heart is similar to that of tincture of digitalis, and its actions on the respiration and intestine and arteries are also similar.

In the cat and frog, it is one fourth as toxic as ouabain, while its power of causing emesis in the pigeon is about one half that of ouabain.

The action of digitalinum verum in these animals is much weaker.

In the guinea-pig, about three times as much digoxin is required to cause 50 per cent mortality when given orally as when given intramuscularly. Its activity given by mouth in this animal is much greater than that of tincture of digitalis.

In the frog ouabain, digoxin and digitoxin were all found to produce cumulative effects. Cumulation with digitalinum verum in the frog was much less marked.

Cumulative effects were also found with digoxin in the guinea-pig with both oral and intramuscular administration. In the case of ouabain, cumulation was observed after intramuscular administration, no attempt being made to determine whether cumulation occurred in oral administration.

Cumulative effects were observed in the cat after oral digoxin.