[Greater oral activity of etilefrine pivalate compared to etilefrine in the cat and dog]

Etilefrine pivalate (K 30 052, Ep) and etilefrine (E) were compared in regard to their effects on the circulation of cats and dogs and in regard to their effects on isolated organs (papillary muscles, atria, vena cava caudalis) of guinea pigs and rabbits. The effects of Ep and E were qualitatively equal. Ep was less effective than E on isolated organs and after intravenous injection, it was however more effective after oral or intraduodenal application. This result is in line with the hypothesis that Ep is inactivated during the first-pass to a smaller extent than E and is split after absorption to E and pivalinic acid.