Diuretic Effect of Metolazone Pre-dosing Versus Concurrent Dosing

Diuretic Effect of Metolazone Pre-dosing Versus Concurrent Dosing With Furosemide: a Pilot Study

The purpose of this study is to examine whether administering metolazone 60 minutes prior to furosemide increases urine output compared with administering metolazone and furosemide concomitantly. Participants will have equal chance of being assigned to each group.

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