A 52-year-old man with hypertension and type 2 diabetes mellitus presents with a blood pressure of 158/98 mmHg. He has mild proteinuria and an eGFR of 58 mL/min/1.73m². Which drug is the first-line choice for this patient to provide both blood pressure control and renal protection?

Explanation

## Rationale for Losartan as First-Line **Key Point:** Angiotensin II receptor blockers (ARBs) like losartan are the preferred first-line agents in hypertensive patients with diabetes and chronic kidney disease because they provide dual cardio-renal protection. ### Mechanism of Renal Protection Losartan blocks AT₁ receptors on the afferent and efferent arterioles of the glomerulus. By selectively dilating the efferent arteriole more than the afferent arteriole, it reduces intraglomerular pressure and protects against proteinuria progression [cite:KD Tripathi 8e Ch 21]. ### Clinical Advantages in This Patient | Feature | Losartan | Amlodipine | Metoprolol | HCTZ | |---------|----------|-----------|-----------|------| | **BP control** | ✓ | ✓ | ✓ | ✓ | | **Proteinuria reduction** | ✓✓ | Limited | Limited | ✗ | | **Renal function preservation** | ✓✓ | Neutral | Neutral | Worsens | | **Glucose metabolism** | Neutral | Neutral | Worsens | Worsens | | **Diabetic nephropathy indication** | FDA approved | Off-label | No | Contraindicated | **High-Yield:** ARBs (and ACE inhibitors) are the only antihypertensive classes with proven benefit in slowing diabetic nephropathy progression. This patient's proteinuria + reduced eGFR makes an ARB or ACE inhibitor mandatory [cite:Harrison 21e Ch 297]. **Clinical Pearl:** Losartan (or any ARB/ACE inhibitor) should be initiated early in diabetic patients with albuminuria, even if BP is only mildly elevated, because the renal protective effect is independent of BP lowering. ### Why Losartan Over ACE Inhibitors? Both are equally effective; losartan is chosen here because it avoids the persistent dry cough seen in ~10% of ACE inhibitor users, improving adherence.