What alpha blocker, such as (alpha-adrenergic blocking agent), is recommended to facilitate stone passage?

Alpha Blockers for Facilitating Stone Passage

Alpha blockers are the preferred agents for medical expulsive therapy (MET) to facilitate ureteral stone passage, with tamsulosin being the most commonly used agent, though tamsulosin, terazosin, and doxazosin have been shown to be equally effective in this setting. 1

Efficacy of Alpha Blockers for Stone Passage

• Alpha blockers significantly increase stone passage rates by 29% (CI: 20% to 37%) compared to control treatments, making them more effective than calcium channel blockers like nifedipine, which only increase passage rates by 9% (CI: 7% to 25%) 1
• The mechanism of action is attributed to ureteral smooth muscle relaxation mediated through alpha-1 receptor blockade, which facilitates stone passage and reduces pain 1
• Alpha blockers are particularly effective for stones larger than 5mm, with studies showing a significant benefit in stone expulsion rate (RR 1.44,95% CI 1.22-1.68) for stones >5mm, but minimal effect for stones ≤5mm 2

Specific Alpha Blockers and Their Comparative Efficacy

• Tamsulosin has been the most extensively studied alpha blocker for MET and is commonly recommended 1
• A small study demonstrated that tamsulosin, terazosin, and doxazosin are equally effective in facilitating stone passage 1
• When comparing alfuzosin to tamsulosin, no significant difference was found in terms of stone-free rate (RR: 0.90; 95% CI, 0.79-1.02) or stone expulsion time 3
• For stones 5-10mm in size, tamsulosin significantly improves stone passage with a number needed to treat of 5 4

Benefits Beyond Stone Passage

• Alpha blockers not only increase stone passage rates but also:
  • Reduce stone passage time 1, 2
  • Limit pain and decrease the incidence of ureteral colic (weighted mean difference -0.81,95% CI -1.24--0.39) 1, 2
  • Reduce the need for subsequent interventions (RR 0.68,95% CI 0.50-0.93) 2

Safety Considerations

• The adverse effects profile is similar among different alpha blockers, with tamsulosin and alfuzosin showing comparable safety profiles (RR: 0.88; 95% CI, 0.61-1.26) 3
• The overall incidence of side effects with alpha blockers does not differ significantly from control groups (RR 1.14,95% CI 0.86-1.51) 2
• Common side effects include dizziness and hypotension, though these are generally well-tolerated 4

Clinical Application

• Alpha blockers should be considered as first-line MET for ureteral stones with a low probability of spontaneous passage 1
• They are particularly beneficial for stones 5-10mm in diameter, while smaller stones (<5mm) may pass spontaneously without intervention 4, 2
• In pediatric patients with uncomplicated ureteral stones ≤10mm, observation with or without MET using alpha-blockers is recommended 1

Adjunctive Use

• Alpha blockers can also be beneficial as adjunctive therapy following ureteroscopic laser lithotripsy, improving stone-free rates (86.5% vs 69.4%) and reducing colic episodes (5.4% vs 22.2%) 5