[Continuous infusion versus bolus injection of loop diuretics in acute heart failure: a literature review]

Intravenous loop diuretics are increasingly used to treat symptoms and signs of fluid overload in acute heart failure, a clinical condition associated with high morbidity and mortality rates. Although diuretic therapy is widely used and strongly recommended by most recent clinical guidelines, prospective studies and randomized clinical trials are lacking and hence there is no reliable evidence regarding the best therapy in terms of doses, ways and methods of administration. With heart failure progression, the efficacy of loop diuretics is impaired by diuretic resistance characterized by a decreased diuretic and natriuretic effect of drugs. This review focuses on the current management of acute heart failure 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. Several available studies 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 plasma drug concentration with a more uniform daily diuretic and natriuretic effect and a greater safety profile (fewer adverse events such as worsening renal failure, electrolyte imbalance, ototoxicity). In addition, the analysis of available literature data did not provide conclusive evidence about the effects on clinical outcomes (mortality, rehospitalization rates, adverse events).