Appropriate Alpha-1 Blockers for Trial Without Catheter (TWOC)
Alfuzosin or tamsulosin are the most appropriate alpha-1 blockers for Trial Without Catheter (TWOC) following acute urinary retention related to BPH. 1
Evidence-Based Recommendation
The 2021 AUA Guidelines provide the strongest and most recent evidence specifically addressing alpha blockers for TWOC. These guidelines clearly state that physicians should prescribe an oral alpha blocker prior to a voiding trial for patients with acute urinary retention related to BPH (Moderate Recommendation; Evidence Level: Grade B) 1.
Specific Alpha Blockers for TWOC
Clinical trials have specifically investigated alfuzosin and tamsulosin for TWOC:
- Alfuzosin: Studies show successful TWOC rates of 60% versus 39% with placebo 1
- Tamsulosin: Studies show successful TWOC rates of 47% versus 29% with placebo 1
Treatment Protocol
- Prescribe alpha blocker (alfuzosin or tamsulosin)
- Continue treatment for at least 3 days prior to attempting TWOC (Expert Opinion) 1
- Inform patients who pass a successful TWOC that they remain at increased risk for recurrent urinary retention 1
Clinical Considerations
Efficacy Comparison
According to the 2003 AUA guidelines, alfuzosin, doxazosin, tamsulosin, and terazosin have equal clinical effectiveness for LUTS secondary to BPH 1. However, for TWOC specifically, the evidence is strongest for alfuzosin and tamsulosin.
Safety Profile Differences
When selecting between alfuzosin and tamsulosin, consider these differences:
- Tamsulosin: Lower probability of orthostatic hypotension but higher probability of ejaculatory dysfunction 1
- Alfuzosin: Better ejaculatory function profile but slightly higher risk of cardiovascular effects 2
Dosing Considerations
- Tamsulosin: 0.4 mg once daily after breakfast (without step-up increments) offers high efficacy with low cardiovascular safety risk 3
- Alfuzosin: Standard dosing for TWOC in studies
Important Caveats
Long-term efficacy unclear: Given the lack of standardized follow-up, the long-term efficacy of alpha blocker therapy in treating AUR is not well established 1
Risk of recurrence: All trials report a significant number of patients with subsequent urinary retention and LUTS after treatment occurring days to months later, necessitating catheterization or surgical procedures 1
Treatment duration: The optimal duration of alpha blocker treatment after successful TWOC remains unknown 4
Double-dose consideration: Some evidence suggests that double-dose alpha blocker therapy (tamsulosin + alfuzosin) may increase TWOC success rates (77% vs 54%) compared to single-dose therapy, though this is not yet in guidelines 5
Conclusion
For patients requiring TWOC following acute urinary retention related to BPH, either alfuzosin or tamsulosin is appropriate based on the strongest current evidence. Treatment should be initiated at least 3 days before attempting TWOC, and patients should be informed about the risk of recurrent retention even after successful TWOC.