Discrimination between five oral frusemide preparations using renal chloride excretion and frusemide recovery

The bioavailabilities of five preparations of frusemide (an aqueous solution, Diurin, Frusid, Lasix and Selemide tablets) were studied in healthy subjects, using Latin square designs and administering doses at weekly intervals. Relative to the solution, Lasix had reduced chloride excretion (0.88) and frusemide recovery (0.80) while Diurin and Frusid had reduced frusemide recoveries (0.90 and 0.92 respectively) There were no other significant differences. Potassium excretion tended to fall as the trials progressed.