Acetazolamide as Add-on Diuretic Therapy in Exacerbations of Chronic Heart Failure: a Pilot Study

BACKGROUND Congestion is the main cause of morbidity in patients with heart failure. Treatment of fluid overload is often challenging in everyday clinical practice. OBJECTIVE The aim of this study was to determine the diuretic effect of acetazolamide in patients with exacerbations of chronic heart failure, in addition to their stable diuretic therapy. METHODS This was a single-center, unblinded study. Patients hospitalized with chronic heart failure exacerbations, with left ventricular ejection fraction (EF) < 50% and signs of volume overload, with a stable dose of diuretics anticipated by the attending physician over the next 4 days, were considered eligible for the study. On day 1, patients were randomized to receive acetazolamide orally, once daily (dose-adjusted to body weight) or no treatment (control group) as add-on diuretic therapy, on days 2 and 3. Diuresis, natriuresis, fluid balance, and symptoms were assessed daily, up to day 4. RESULTS Twenty patients (mean ± standard deviation age 72 ± 11.6 years; 85% men; mean EF 33.8 ± 11.4%; mean N-terminal pro-B-type natriuretic peptide 8064 ± 5593 pg/mL; mean intravenous furosemide dose 105 ± 55 mg) were enrolled. Diuresis, natriuresis, fluid balance, and symptoms were stable on days 1-4 in the control group. An increase in diuresis and natriuresis, and a greater change in fluid balance after administration of acetazolamide, were observed in patients randomized to acetazolamide. On day 4, there was a significant difference in fluid balance between the acetazolamide and control groups (-666 ± 1194 mL vs. +332 ± 705 mL; p = 0.035), and dyspnea was lower in patients receiving acetazolamide (visual scale, p < 0.001; 5-point Likert scale, 1.444 vs. 2.222; p = 0.04) CONCLUSIONS: In this pilot study, the addition of acetazolamide to the background diuretic regimen in patients with chronic heart failure exacerbations produced an additional diuretic effect and alleviation of dyspnea.