Alpha-Blockers and Beta-3 Agonists: Generic and Brand Names
For alpha-blockers, prescribe alfuzosin, doxazosin, silodosin, tamsulosin, or terazosin (generic names); for beta-3 agonists, prescribe mirabegron (Myrbetriq) or vibegron (Gemtesa).
Alpha-Blockers for LUTS/BPH
The AUA guideline explicitly recommends five alpha-blockers as treatment options for bothersome moderate to severe lower urinary tract symptoms 1:
Generic and Brand Names:
- Alfuzosin (Uroxatral)
- Doxazosin (Cardura)
- Silodosin (Rapaflo)
- Tamsulosin (Flomax)
- Terazosin (Hytrin)
Key Prescribing Considerations:
All five are equally effective for symptom improvement (4-7 point IPSS reduction vs 2-4 points for placebo), so selection should be based on patient-specific factors 1:
- Ejaculatory dysfunction risk: Silodosin and tamsulosin have higher rates of ejaculatory dysfunction due to their alpha-1A selectivity
- Blood pressure effects: Doxazosin and terazosin require dose titration due to greater cardiovascular effects; tamsulosin and alfuzosin do not require titration 2
- Cataract surgery: All alpha-blockers carry risk of intraoperative floppy iris syndrome (IFIS). Delay initiation until after planned cataract surgery 1
Follow-up timing: Schedule first visit at 4 weeks for alpha-blockers (fast-onset drugs) 1
Beta-3 Agonists for Overactive Bladder
Generic and Brand Names:
- Mirabegron (Myrbetriq) - 25mg or 50mg daily
- Vibegron (Gemtesa) - 75mg daily
Clinical Context:
Beta-3 agonists are recommended for overactive bladder management and can be used as monotherapy or in combination with alpha-blockers in patients with both BPH and OAB 3. Mirabegron has similar efficacy to antimuscarinics but with a more favorable adverse effect profile, particularly avoiding anticholinergic side effects like dry mouth, constipation, and cognitive impairment 4.
Combination Therapy:
For patients with both BPH and OAB symptoms, prescribe an alpha-blocker plus a beta-3 agonist rather than antimuscarinic medications when possible, as this combination avoids anticholinergic burden while effectively treating both conditions 3.
Common Pitfall:
Do not confuse beta-3 agonists (used for bladder relaxation) with beta-blockers (used for cardiovascular conditions). They have opposite mechanisms and completely different indications.