Metolazone Versus Intravenous Chlorothiazide for Decompensated Heart Failure Sequential Nephron Blockade: A Retrospective Cohort Study.

Background: Metolazone and intravenous (IV) chlorothiazide are commonly used diuretics for sequential nephron blockade (SNB) in patients with acute decompensated heart failure (ADHF). Previous studies suggest metolazone may be comparable with chlorothiazide in terms of efficacy and safety. The objective of this study was to determine whether IV chlorothiazide is superior to metolazone in increasing net urine output (UOP) of hospitalized patients with ADHF.
Methods and Results: This retrospective cohort study included hospitalized patients with ADHF and evidence of loop diuretic resistance in a tertiary academic medical center. The primary end point was the change in net 24-hour UOP in patients treated with IV chlorothiazide compared with metolazone. The relative cost of chlorothiazide doses and metolazone doses administered during SNB was a notable secondary end point. The median change in net 24-hour UOP in the IV chlorothiazide group was -1481.9 mL (interquartile range -2696.0 to -641.0 mL) and -1780.0 mL (interquartile range -3084.5 to -853.5 mL) in the metolazone group (P = .05) across 220 hospital encounters. The median cost of chlorothiazide and metolazone doses used during SNB was $360 and $4, respectively (P < .01).
Conclusions: Chlorothiazide was not superior to metolazone in changing the net 24-hour UOP of patients with ADHF and loop resistance. Preferential metolazone use in SNB is a potential cost-saving measure.
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