Digitoxin plasma half-life in the dog after administration of toxic doses.

Digitoxin plasma levels were determined in the dog by radioimmunoassy after i.v. infusion of this cardenolide in toxic amounts (388 +/- 13 mug/kg). Plasma values found immediately after the administration of this dose were 588.5 +/- 91 ng/ml and attained very low levels (10 ng/ml) 96 h later. The dominant half-life of digitoxin in the dog was found to be 49.6 +/- 6.5 h, but this value was attained only in the final part of our study. The results found are compared with previous data and controversial aspects are discussed.