A 58-year-old man with Stage 3b CKD (eGFR 35 mL/min/1.73m²) and hypertension presents with proteinuria of 2.5 g/day. His serum potassium is 4.8 mEq/L and creatinine is 1.8 mg/dL. Which is the drug of choice to slow progression of his kidney disease?

Explanation

## Rationale for ACE Inhibitor as First-Line in CKD with Proteinuria **Key Point:** ACE inhibitors (and ARBs) are the gold-standard first-line antihypertensives in CKD with proteinuria because they reduce intraglomerular pressure and proteinuria independent of systemic blood pressure reduction. **High-Yield:** The mechanism of renoprotection involves: 1. Preferential dilation of the efferent arteriole (reducing glomerular hyperfiltration) 2. Reduction of proteinuria by 30–50% 3. Slowing of GFR decline by ~50% over 2–3 years 4. Anti-inflammatory and anti-fibrotic effects on the glomerulus **Clinical Pearl:** In this patient, ramipril is indicated because: - Proteinuria >1 g/day is a strong indication for ACE-I/ARB - eGFR 30–59 mL/min/1.73m² (Stage 3b) is ideal for ACE-I initiation - Serum K^+^ is normal (4.8 mEq/L), so no contraindication - Creatinine rise of 20–30% in first 2 weeks is expected and acceptable **Mnemonic:** **ACEI-CKD** = **A**CE **I**nhibitor is **C**ore therapy in **C**hronic **K**idney **D**isease with proteinuria. ### Comparison with Other Antihypertensives | Drug Class | Mechanism | Proteinuria Reduction | Renoprotection | Use in CKD | |---|---|---|---|---| | **ACE-I / ARB** | Efferent arteriole dilation | 30–50% | Yes (proven) | **First-line** | | Calcium channel blocker (amlodipine) | Systemic vasodilation | Minimal (<10%) | No | Second-line if ACE-I contraindicated | | Hydralazine | Direct vasodilation | Minimal | No | Not recommended as monotherapy | | Alpha-blocker (doxazosin) | Peripheral α1 blockade | Minimal | No | Not for CKD hypertension | **Warning:** Do NOT use ACE-I/ARB if eGFR <15 mL/min/1.73m² without specialist input, or if baseline K^+^ >5.5 mEq/L, or in pregnancy.