Unchanged absorption of digoxin tablets in patients with cardiac failure

In 6 patients with severe left-sided cardiac failure the absorption of drug from digoxin tablets was assessed by simultaneous administration of a commercially available tablet and of an intravenous tracer dose before and during therapy. Lag time, peak time, and dose-normalized increase in plasma concentration did not change in spite of clinical improvement. Two independent measures of the extent of availability, based on plasma and urine measurements, also remained unchanged and their average was similar to that reported for normals. There was, however, a great interindividual variability in absorption. We conclude that the absorption of digoxin tablets is unchanged in patients with left-sided cardiac failure.