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.