Efficacy and safety of loop diuretic therapy in acute decompensated heart failure: a clinical review

Intravenous loop diuretics are widely used to treat the symptoms and signs of fluid overload in acute heart failure (AHF). Although diuretic therapy is widely used and strongly recommended by most recent clinical guidelines, prospective studies and randomized clinical trials are lacking and so reliable evidence is missing about the best therapy in terms of doses and methods of administration. In addition, clinical efficacy and safety outcomes are often affected by the presence of contrasting evidence. The efficacy of loop diuretics is impaired by diuretic resistance characterized by a decreased diuretic and natriuretic effect. This review focuses on the current management of AHF with diuretic therapy. Continuous diuretic infusion seems to be a good choice, from a pharmacokinetic point of view, when fluid overload is refractory to conventional therapy. Some available evidence comparing bolus injection to continuous infusion of loop diuretics proved the latter to be an effective and safe method of administration. Continuous infusion seems to produce a constant plasmatic concentration of drug with a more uniform daily diuretic and natriuretic effect and a greater safety profile (fewer adverse events such as worsening renal failure, electrolyte imbalances, ototoxicity). The analyses of the published studies did not provide conclusive data about the effects on clinical outcomes (mortality, rate of hospital readmissions, length of hospital stay and adverse events). Furthermore, recent studies focus their attention on alternative strategies of fluid removal, such as vasopressin antagonists, adenosine antagonists and ultrafiltration but available data are often inconclusive.