A 52-year-old man with benign prostatic hyperplasia and hypertension presents with nocturia and weak urinary stream. Which drug would be the preferred choice to address both conditions simultaneously?

Explanation

## Mechanism of Action **Key Point:** Doxazosin is a non-selective α₁-adrenergic antagonist that blocks α₁A and α₁B receptors on vascular smooth muscle and prostatic tissue. ## Dual Benefit in BPH + Hypertension Doxazosin provides two therapeutic advantages: 1. **Prostatic symptom relief** — α₁A receptor blockade in the prostate reduces smooth muscle tone, improving urinary flow and reducing nocturia 2. **Blood pressure reduction** — α₁B receptor blockade on vascular smooth muscle causes vasodilation, lowering systemic vascular resistance ## Comparison with Alternatives | Drug | Mechanism | BPH Relief | BP Reduction | Notes | |------|-----------|-----------|--------------|-------| | **Doxazosin** | Non-selective α₁ antagonist | ✓ | ✓ | First-line for dual pathology | | Finasteride | 5α-reductase inhibitor | ✓ (slow onset) | ✗ | No antihypertensive effect; takes 6 months | | Tamsulosin | Selective α₁A antagonist | ✓ | ✗ | Minimal BP effect; uroselective | | Oxybutynin | Anticholinergic | ✗ | ✗ | For overactive bladder, not BPH | **High-Yield:** Doxazosin and terazosin (non-selective α₁ antagonists) are the only drugs that treat both BPH and hypertension. Tamsulosin, though excellent for BPH alone, lacks meaningful antihypertensive action due to its α₁A selectivity. **Clinical Pearl:** The ALLHAT trial showed that doxazosin was less effective than other antihypertensives for cardiovascular protection in hypertension, so it is reserved for patients with concurrent BPH. **Warning:** Oxybutynin is an anticholinergic used for overactive bladder (detrusor overactivity), not BPH. It would worsen urinary retention in BPH.