Diuretic Effect of Metolazone Pre-dosing Versus Concurrent Dosing

Diuretic resistance is common among patients with acute decompensated heart failure, and one
strategy for overcoming this phenomenon is sequential nephron blockade with loop plus
thiazide-type diuretics. Metolazone is an oral thiazide-type diuretic commonly used for this
purpose. Due to its delayed absorption, some clinicians suggest that metolazone be given
30-60 minutes prior to the loop diuretic. However, the efficacy and safety of such a strategy
has not been investigated despite its added complexity. The purpose of this study is to
investigate whether pre-dosing with metolazone confers a difference in efficacy and safety
compared to administering it at the same time as furosemide.

Inclusion Criteria:

- Admission within 48 hours for acute decompensated heart failure with at least one
symptom and one sign of volume overload

- Receipt of loop diuretic prior to admission

- Plan to administer furosemide 120 - 160 mg IV bolus twice daily over the next 24 hours
with additional diuresis deemed necessary

- If patient is concurrently administered intravenous vasodilator or inotrope, the dose
of vasodilator or inotrope must be stable for 6 hours prior to enrollment with a plan
to continue the same dose for the 24 hour duration of this study

Exclusion Criteria:

- Metolazone prescribed prior to admission

- Receipt of continuous intravenous infusion of furosemide

- Cirrhosis or end stage renal disease

- Non-English speaking patients