The evidence base for diuretic therapy.

AgeþBUN5Lasix Dose 1 Oh to have such a simple equation to assist in the determination of appropriate diuretic regimens. Although this ‘‘law’’ was written O30 years ago, it seems as if the evidence for managing diuretics has not advanced much beyond this humorous attempt to quickly treat edema in elderly patients. Diuretics are first-line therapy for heart failure (HF) because they improve symptoms rapidly. Within hours or days of administration, diuretics increase urinary sodium excretion, decrease physical signs of fluid retention, and often improve exercise tolerance in patients with HF. Few patients with HF will be able to maintain dry weight without the use of diuretics, and the appropriate use of diuretics is fundamental to the successful use of other drugs for the treatment of HF. 2 Diuretics also have potential detrimental effects, such as vasoconstriction, electrolyte disturbances, neurohormonal activation, and worsened renal function; these issues have been well reviewed. 3e5 Effective use of diuretics entails balancing benefits and risks. Diuretics are so essential to the care of the patient with HF that investigation of their use is challenging; therefore, there are no long-term randomized controlled trials that have evaluated morbidity or mortality outcomes related to diuretic therapy. Despite the lack of long-term outcome studies, professional guidelines recognize the need for diuretics to improve symptoms and quality of life, 4 yet practice patterns vary widely regarding routine clinical use of diuretic therapy. Two recent papers shed light on a few of these common practice patterns. The recent Diuretic Optimization Strategies Evaluation in Acute Heart Failure (DOSE) trial providedevidence to assist in the practical management of administration and dosing of intravenous(IV)loopdiureticsinacuteHF. 6 Thismulticenter randomized controlled trial of 308 patients hospitalized for acute HFcompared:1) continuousIVinfusionoffurosemide with the administration of IV boluses every 12 hours; and 2) alow-dosewithahigh-dosestrategy.Primaryoutcomeswere patients’ global assessment of symptoms and the change in serum creatinine from baseline to 72 hours. There were no significant differences in these outcomes when diuretics were given by bolus compared with continuous infusion or when diuretics were given at higher doses compared with lower doses. The high-dose strategy was associated with greater relief of dyspnea and greater fluid and weight loss, as well as with a transient worsening of renal function. Thus, in patients with acute HF, we now have evidence that a high-dose regimen may relieve symptoms more quickly, without short-term adverse outcomes, and that administration of bolus doses may be moreconvenient than and equally as effective as a continuous diuretic infusion. 7