What are the most commonly used selective α1‑adrenergic antagonists and their typical starting doses for hypertension and benign prostatic hyperplasia?

Most Common Selective α1-Adrenergic Receptor Antagonists

The four most commonly used selective α1-adrenergic antagonists are tamsulosin, alfuzosin, doxazosin, and terazosin—all considered equally effective with similar clinical outcomes for treating lower urinary tract symptoms secondary to benign prostatic hyperplasia. 1

Primary Agents and Their Characteristics

First-Line α1-Blockers

• Tamsulosin is the most widely prescribed selective α1A-adrenergic antagonist, typically started at 0.4 mg once daily, with the option to increase to 0.8 mg for enhanced efficacy 1, 2

• Alfuzosin is an appropriate treatment option with similar efficacy to tamsulosin and potentially lower risk of orthostatic hypotension, making it suitable for patients with cardiovascular comorbidities 1, 2

• Doxazosin is a non-selective α1-antagonist that requires dose titration, with clinical data supporting efficacy up to 8 mg daily 1

• Terazosin is another titratable α1-blocker with demonstrated efficacy at doses up to 10 mg daily 1

• Silodosin (8 mg daily) is a highly selective α1A-antagonist with greater potency but higher rates of ejaculatory dysfunction compared to other agents 1, 2

Comparative Efficacy and Safety Profiles

Symptom Improvement

• All four primary agents (tamsulosin, alfuzosin, doxazosin, terazosin) produce similar symptom relief, with an average 4-6 point improvement in the AUA Symptom Index that patients perceive as meaningful 1, 2

• Efficacy is dose-dependent for the titratable agents (doxazosin and terazosin), with higher doses producing greater observed improvement 1

Adverse Event Differences

• Tamsulosin has a lower probability of orthostatic hypotension but a higher probability of ejaculatory dysfunction compared to other α1-blockers 1, 2

• Silodosin has the highest rates of ejaculatory dysfunction but the lowest rates of orthostatic hypotension among all α1-blockers 1, 2

• Common adverse events across all agents include orthostatic hypotension, dizziness, asthenia (tiredness), ejaculatory problems, and nasal congestion 1, 2

Critical Clinical Considerations

Cardiovascular Effects

• In men with hypertension and cardiac risk factors, doxazosin monotherapy was associated with higher incidence of congestive heart failure compared to other antihypertensive agents 1

• α1-blocker therapy for lower urinary tract symptoms should not be assumed to constitute optimal management of concomitant hypertension, requiring separate hypertension management 1

Ophthalmologic Concerns

• All α1-blockers carry risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery 2

• Patients planning cataract surgery should delay α1-blocker initiation until after the procedure, and must inform their ophthalmologist if already taking these medications 2

Agents NOT Recommended

• Prazosin has insufficient data to support its use as a treatment option for lower urinary tract symptoms secondary to benign prostatic hyperplasia 1

• Phenoxybenzamine (non-selective α-blocker) is not recommended for treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia 1

Typical Starting Doses

For Benign Prostatic Hyperplasia

• Tamsulosin: 0.4 mg once daily (can increase to 0.8 mg) 1, 2
• Alfuzosin: Standard dosing per FDA approval 1
• Doxazosin: Titrate up to 8 mg daily 1
• Terazosin: Titrate up to 10 mg daily 1
• Silodosin: 8 mg once daily 1

Reassessment Timeline

• Follow-up at 4 weeks to assess symptom improvement (IPSS), quality of life, adverse effects, and consider post-void residual and uroflowmetry if available 2