The Anti-aldosterone Effects of Torsemide Do Not Lead to Detectable Improvement in Potassium Losses in Patients Treated for Decompensated Heart Failure

Abstract

Background: Loop diuretics are the mainstay of treatment for volume overload in heart failure. Data is limited as to which loop diuretic is the preferred agent. Studies in animal models suggest that torsemide may have a positive anti-aldosterone effect, through receptor antagonism and inhibition of aldosterone secretion. However, the clinical significance of these effects in human heart failure is unknown. Hypothesis: If the anti-aldosterone effects of torsemide are clinically meaningful, potassium losses from torsemide should be reduced compared to other loop diuretics lacking anti-aldosterone effects. Methods: We studied 75 hospitalized heart failure patients treated with loop diuretics. Within this sample, 51 patients received bumetanide, 25 torsemide, and 12 furosemide with 13 patients receiving both bumetanide and torsemide on different days. A spot urine was collected prior to diuretic administration and then a timed 6-hour urine collection was performed after diuretic administration to determine total potassium excretion. Values reported represent median (quartile 1 quartile 4). Results: The doses of bumetanide, torsemide, and furosemide received were 3 mg (2-4 mg), 40 mg (20-70 mg) and 40 mg (25-80 mg), respectively. There was no significant difference in total potassium excretion and the potassium to sodium excretion ratio between the patients on torsemide, bumetanide and furosemide (Table 1). There was also no significant difference in fractional excretion of potassium (FEK) or change in FEK between patients on different diuretics (Table 1). In the subgroup of patients that received both bumetanide and torsemide on different days (n513) total potassium excretion (p50.30), potassium to sodium excretion ratio (p50.58), FEK (p50.41), and change in FEK (p50.74) were similar across diuretics. Conclusion: Torsemide did not produce a detectable change in total potassium excretion or potassium handling compared to furosemide or bumetanide. Acute anti-aldosterone effects of torsemide do not appear to be clinically significant in heart failure patients receiving high dose loop diuretics.