Diuretic Resistance Strategy — EECC MCQ

Correct answer: A — Diuretic resistance is defined as failure to achieve adequate decongestion despite escalating loop diuretic doses; the next step is doubling the IV furosemide dose or adding a sequential nephron blockade agent (metolazone or IV chlorothiazide)

Diuretic resistance in acute HF is common and clinically important. The 2023 ESC HF Guidelines recommend a stepwise approach: (1) Ensure adequate IV dose (many patients receive insufficient doses — bioavailability of oral furosemide is variable; IV provides 100% bioavailability); (2) Double the IV dose if response inadequate (spot urine sodium <50 mmol/L at 2 hours predicts poor response); (3) Add sequential nephron blockade — a thiazide or thiazide-like diuretic (metolazone 2.5-10 mg PO or IV chlorothiazide) blocks sodium reabsorption at a different site (DCT), creating synergistic natriuresis; (4) Consider continuous IV furosemide infusion; (5) Acetazolamide (ADVOR trial — adding acetazolamide to IV furosemide improved decongestion). Monitor for hypokalaemia and hyponatraemia with combination diuretics.

Reference: ESC (2023): HF Guidelines; ADVOR Trial