Will a 1.4 x 7 mm stone at the left ureteropelvic junction pass with Flomax (tamsulosin)?

Medical Expulsive Therapy for a 1.4 x 7 mm Stone at the Left Ureteropelvic Junction

Alpha-blockers like tamsulosin (Flomax) significantly increase the likelihood of spontaneous passage of a 1.4 x 7 mm stone at the ureteropelvic junction, with an expected absolute increase of 29% in stone passage rates compared to conservative management alone. 1

Stone Characteristics and Passage Probability

• Size consideration:
  • At 7 mm length, this stone is in the moderate size range
  • For proximal ureteral stones <10 mm, spontaneous passage is possible but less likely than for smaller stones
  • Location at the ureteropelvic junction (proximal ureter) affects passage rates

Evidence for Medical Expulsive Therapy (MET)

• Alpha-blockers are the preferred agents for MET 1, 2
• Tamsulosin works by relaxing ureteral smooth muscle through alpha-1 receptor blockade 2
• Meta-analysis shows:
  • 29% absolute increase in stone passage rates with alpha-blockers compared to controls (statistically significant) 1
  • Tamsulosin reduces stone passage time and limits pain 1, 2

Efficacy for Proximal Ureteral Stones

• For proximal ureteral stones specifically:
  • Tamsulosin increased stone expulsion rate to 74.1% vs. 46.3% with conservative management alone 3
  • Mean time to stone passage was significantly shorter with tamsulosin (14.3 days vs. 19.6 days) 3
  • On multivariate analysis, tamsulosin was the only statistically significant predictor of stone expulsion (OR=3.198, p=0.021) 3

Treatment Algorithm

1. First-line approach: Trial of tamsulosin 0.4 mg daily for up to 6 weeks

   • Monitor for stone passage
   • Provide appropriate pain management (NSAIDs preferred as first-line) 2
   • Ensure adequate hydration (>2L/day) 2

2. If unsuccessful after 4-6 weeks:

   • Consider interventional approaches:
     • Ureteroscopy (URS) with laser lithotripsy - higher stone-free rates but slightly higher complication risk 1, 2
     • Shock Wave Lithotripsy (SWL) - 82% stone-free rate for proximal ureteral stones 2

Important Considerations

• Monitor for signs of infection or complete obstruction requiring urgent intervention
• Tamsulosin side effects are generally mild and transient 4
• Maximum duration of conservative therapy should be limited to 6 weeks to avoid irreversible kidney injury 1
• For patients with bleeding disorders or on anticoagulation, URS would be the preferred interventional approach if MET fails 1

Follow-up Recommendations

• Urological follow-up within 1-2 weeks with imaging to assess stone position and progression 2
• Patient education on warning signs requiring immediate medical attention:
  • Fever (sign of infection)
  • Uncontrolled pain
  • Persistent nausea/vomiting
  • Signs of urinary obstruction 2

In conclusion, tamsulosin is an effective medical expulsive therapy for a 1.4 x 7 mm stone at the ureteropelvic junction, significantly increasing the probability of spontaneous passage and reducing time to passage.