Metabolic and toxicological considerations for diuretic therapy in patients with acute heart failure.

INTRODUCTION: Diuretics are widely recommended in patients with acute heart failure (AHF). However, loop diuretics predispose patients to electrolyte imbalance and hypovolemia, which in turn leads to neurohormonal activation and worsening renal function (WRF). Unfortunately, despite their widespread use, limited data from randomized clinical trials are available to guide clinicians with the appropriate management of this diuretic therapy. AREAS COVERED: This review focuses on the current management of diuretic therapy and discusses data supporting the efficacy and safety of loop diuretics in patients with AHF. The authors consider the challenges in performing clinical trials of diuretics in AHF, and describe ongoing clinical trials designed to rigorously evaluate optimal diuretic use in this syndrome. The authors review the current evidence for diuretics and suggest hypothetical bases for their efficacy relying on the complex relationship among diuretics, neurohormonal activation, renal function, fluid and sodium management, and heart failure syndrome. EXPERT OPINION: Data from several large registries that evaluated diuretic therapy in hospitalized patients with AHF suggest that its efficacy is far from being universal. Further studies are warranted to determine whether high-dose diuretics are responsible for WRF and a higher rate of coexisting renal disease are instead markers of more severe heart failure. The authors believe that monitoring congestion during diuretic therapy in AHF would refine the current approach to AHF treatment. This would allow clinicians to identify high-risk patients and possibly reduce the incidence of complications secondary to fluid management strategies.