Interaction between frusemide and aspirin

Abstract 1. 1. The effects of the combination of aspirin and frusemide were studied on salicylate excretion by aspirin and on the diuresis and excretion of K + and Na + by frusemide in normal human subjects. 2. 2. There was a paradoxical net reduction in the natriuresis induced by aspirin, from 29.4 ± 3.57 m-equiv and frusemide from 31.9 ± 1.27 to 23.7 ± 1.56 m-equiv on combined administration. 3. 3. Frusemide caused a reduction of the kalliuretic effect induced by aspirin from 48.86 ± 8.36 to 18.3 ± 3.76 m-equiv. 4. 4. The amount of salicylate excreted over a 3-hr period gave increases of 9.6 and 12.0% when aspirin was administered before frusemide and vice versa, respectively, while there was a 30.4% reduction when administered concomitantly.