Ouabain Plasma Level Kinetics and Removal by Dialysis in Chronic Renal Failure

Abstract

Ouabain plasma level kinetics and removal by dialysis were studied in 14 dialysis-dependent patients with chronic renal failure. Each received one 400-µg intravenous dose of unlabeled ouabain (9 patients also received 83 µCi of ₃H-ouabain) at the onset of a routine 4-hour hemodialysis. Plasma concentration fell rapidly the first few hours, and after 5 to 10 hours declined exponentially with a mean half-life of 50 ± 19 (SD) hours. Ouabain recovery in dialysis bath was 11.5% ± 2.2% the first 2 hours and only 3.4% ± 0.5% the next 2 hours after an intravenous dose, due to rapid removal of ouabain from the extracellular fluid compartment by tissue uptake. Hence, hemodialysis is relatively ineffective for reducing ouabain body stores. Ouabain elimination in patients with chronic renal failure is significantly slower than in normal subjects (P < 0.01), but significantly more rapid than that reported for digoxin (P < 0.01) and digitoxin (P < 0.01) in patients with chronic renal failure, a potentially useful characteristic in treating acute cardiac problems among such patients.