skip to main content

Thiazide Efficacy in CKD — EECC MCQ

Instant feedback + full explanation. One question, done properly.

ModerateHypertension & Preventive CardiologyThiazide Efficacy in CKDEECC

A 65-year-old man with hypertension and CKD stage 3b (eGFR 35 mL/min) is on lisinopril 20 mg and amlodipine 10 mg. His BP is 145/92 mmHg. A thiazide diuretic is considered as the third agent. Should a thiazide or loop diuretic be used at this eGFR?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Thiazide-like diuretics (chlorthalidone, indapamide) remain effective at eGFR 30-45 mL/min and are preferred over HCTZ which loses efficacy below eGFR ~30; loop diuretics (furosemide, torasemide) are needed when eGFR falls below ~30 mL/min for adequate natriuresis

The traditional teaching that thiazide diuretics are ineffective below eGFR 30 mL/min has been revised. The 2024 ESC Hypertension Guidelines and KDIGO guidelines note: (1) hydrochlorothiazide (HCTZ) loses significant efficacy below eGFR ~30; (2) chlorthalidone and indapamide (thiazide-LIKE diuretics) remain effective at lower eGFR (the CLICK trial showed chlorthalidone was effective in advanced CKD, eGFR 15-29 mL/min); (3) loop diuretics (furosemide, torasemide, bumetanide) are increasingly needed as eGFR declines below ~30 for adequate volume control and natriuresis. At eGFR 30-45 (this patient), chlorthalidone or indapamide is a reasonable third agent. Monitoring: electrolytes (thiazides cause hypokalaemia — offset by concurrent ACEi) and renal function closely. Combining a thiazide and loop diuretic ('sequential nephron blockade') may be needed for resistant oedema in advanced CKD.

Reference: ESC (2024): Hypertension; KDIGO; CLICK Trial