Drug interactions in intestinal absorption of 3H-digitoxin in rats.

The absorption of 3H-digitoxin from perfused rat small intestine was inhibited by probenecid (1.0 x 10-2 M), ethacrynic acid (0.5 x 10-3 M), and mersalyl (8.0 x 10-3 M) indicating that digitoxin absorption is at least partly an active process.