Increased Spironolactone in Advanced Heart Failure: Effect of Doses Greater than 25 mg/Day on Plasma Potassium Concentration

Abstract

Background: Daily doses of spironolactone higher than 25 mg are rarely used in heart failure (HF) patients, presumably due to the concern for hyperkalemia. However, in advanced HF, doses ≥50 mg have been found to be necessary to produce natriuresis. The aim of the present study was to examine the safety of natriuretic doses of spironolactone (50-200 mg) on serum potassium concentration in New York Heart Association (NYHA) class III/IV HF patients over several weeks.

Methods: 18 patients with advanced HF received 50-200 mg of spironolactone in addition to standard treatment. Serum electrolytes, BUN and serum creatinine were assessed at baseline, during increased doses of spironolactone and at the 1-month follow-up.

Results: During a total of 738 patient-weeks, there was no significant increase in mean serum potassium (4.0 vs. 4.2 mEq/l) or serum creatinine (1.3 vs. 1.4 mg/dl). However, in 3 patients, spironolactone treatment was stopped due to a mean increase in serum creatinine (1.9 vs. 2.6 mg/dl) and in one of them, an increase in serum potassium (4.4 vs. 5.2 mEq/l) was noted.

Conclusion: Increased doses of spironolactone are generally safe during outpatient follow-up in selected patients with advanced HF, who are receiving treatment with ACE inhibitors, beta-blockers, and loop diuretics.

Keywords: Heart failure; Hyperkalemia; Spironolactone.