A 58-year-old man with benign prostatic hyperplasia (BPH) presents with nocturia (×4/night), weak urinary stream, and incomplete emptying. He has no contraindications to alpha blockers. Which drug is the preferred first-line alpha blocker for symptomatic BPH in this patient?

Explanation

## First-Line Alpha Blocker for BPH **Key Point:** Tamsulosin is the preferred first-line alpha blocker for symptomatic BPH because it is uroselective (selective for α1A-adrenergic receptors in the prostate) and causes minimal systemic vasodilation. ### Why Tamsulosin Is Superior | Feature | Tamsulosin | Non-selective α1 blockers (Doxazosin, Terazosin) | Irreversible blockers (Phenoxybenzamine) | |---------|-----------|--------------------------------------------------|------------------------------------------| | **Selectivity** | α1A-selective (uroselective) | Non-selective (α1A, α1B, α1D) | Non-selective | | **Systemic hypotension** | Minimal | Significant (first-dose syncope risk) | Severe | | **LUTS improvement** | Excellent | Good | Not used for BPH | | **Onset** | 1–2 weeks | 2–4 weeks | Not applicable | | **Dosing** | 0.4–0.8 mg OD | 1–8 mg OD | Not applicable | **High-Yield:** Tamsulosin's α1A selectivity means it preferentially blocks receptors in the prostate smooth muscle (causing symptom relief) while sparing vascular α1B receptors (avoiding orthostatic hypotension and syncope). **Clinical Pearl:** Although doxazosin and terazosin are also effective for BPH, they carry a higher risk of first-dose syncope and orthostatic hypotension due to non-selective vasodilation. Tamsulosin is therefore preferred as first-line monotherapy. ### Mechanism in BPH Alpha blockers relax smooth muscle in the prostate capsule and bladder neck via α1-adrenergic antagonism, reducing outlet obstruction and improving urine flow rate and symptom scores (IPSS). **Mnemonic: TAMS** — **T**amsulosin, **A**lpha1A-selective, **M**inimal hypotension, **S**ymptomatic BPH first-line.