STONE DISEASE

Tamsulosin treatment increases clinical success rate of single extracorporeal shock wave lithotripsy of renal stones
Gravina GL, Costa AM, Ronchi P, Galatioto GP, Angelucci A, Castellani D, Narcisi F, Vicentini C
Department of Surgery, University of L’Aquila, L’Aquila, Italy
Urology. 2005; 66: 24-8

• Objectives: To design a randomized, no-treatment, controlled, prospective study to determine whether the administration of tamsulosin, as adjunctive medical therapy, increases the efficacy of one extracorporeal shock wave lithotripsy (ESWL) session to treat renal stones and decreases the use of analgesic drugs after the procedure.
• Methods: A total of 130 patients underwent a single ESWL session to treat solitary radiopaque renal stones 4 to 20 mm in diameter. After treatment, all patients were randomly assigned to receive our standard medical therapy alone (controls) or in association with 0.4 mg tamsulosin daily for a maximum of 12 weeks. All 130 patients were followed up for 3 months or until an alternative treatment was given.
• Results: Of the 130 patients, 78.5% of those receiving tamsulosin and 60% of controls had achieved clinical success at 3 months (P = 0.037). When we stratified patients according to stone size, for those with a stone size larger than 10 mm, the success rate was significantly greater in the tamsulosin group (P = 0.028). Renoureteral colic occurred in 76.9% of patients treated with standard therapy but in only 26.1% of those receiving tamsulosin (P < 0.001). The mean cumulative diclofenac dose was 375 mg per patient in the tamsulosin group and 675 mg per patient in the control group (P < 0.001).
• Conclusions: The results of our study have demonstrated that tamsulosin therapy, as an adjunctive medical therapy after ESWL, is more effective than lithotripsy alone for the treatment of patients with large renal stones and is equally safe. In addition, our results also indicated that adjunctive treatment with tamsulosin could decrease the use of analgesic drugs after ESWL.
  
  
• Editorial Comment
  The benefit of pharmacotherapy in promoting spontaneous passage of ureteral calculi has been demonstrated in a number of randomized clinical trials. Medical regimens consisting of calcium channel blockers in conjunction with corticosteroids, and alpha-adrenergic antagonists with or without corticosteroids, have proven efficacy in facilitating ureteral stone passage, and are being increasing administered to patients presenting with an acute stone event. In a prospective, randomized trial, Gravina and colleagues evaluated the efficacy of the alpha-1-adrenergic receptor antagonist tamsulosin compared with no treatment in patients undergoing shock wave lithotripsy (SWL) for isolated, non-lower pole, renal calculi between 4 and 20 mm in size, in whom corticosteroids were additionally administered to all patients. Stone free rates at 3 months by KUB/renal ultrasound or IVP were superior in the tamsulosin group compared with the control group (78.5% versus 60%, respectively). When stratified by stone size, however, the difference between groups was statistically significant only in patients with larger stones (between 11 and 20 mm). Furthermore, the occurrence of renal colic and the need for analgesics was reduced in the tamsulosin group compared with the control group.
  This intriguing study and others have explored the use of adjuvant pharmacotherapy, including potassium citrate (1) and nifedipine and corticosteroids (2), which are aimed at increasing the efficacy of SWL by improving stone clearance. In the kidney, potassium citrate likely acts to reduce aggregation of stone fragments, thereby facilitating discharge of fragments after SWL. In the ureter, nifedipine and deflazacort (2) and tamsulosin (3) are presumed to inhibit uncontrolled contraction of ureteral smooth muscle thereby facilitating spontaneous stone passage. The mechanism of action of tamsulosin and corticosteroids in promoting passage of fragments after SWL of renal calculi is less readily apparent. Although this drug regimen may facilitate passage of fragments that might otherwise hang up in the ureter, the mechanism by which it enhances clearance of fragments from the collecting system is not clear. Alpha-adrenergic receptors have been identified in the ureter but their presence in the collecting system has not been reported. Further investigation into the action of tamsulosin on the renal collecting system and is warranted, as are further trials looking at the role of tamsulosin alone as adjuvant therapy after SWL.

References
1. Soygur T, Akbay A, Kupeli S: Effect of potassium citrate therapy on stone recurrence and residual fragments after shockwave lithotripsy in lower caliceal calcium oxalate urolithiasis: a randomized controlled trial. J Endourol. 2002; 16: 149-152.
2. Porpiglia F, Destefanis P, Fiori C, Scarpa RM, Fontana D: Role of adjunctive medical therapy with nifedipine and deflazacort after extracorporeal shock wave lithotripsy of ureteral stones. Urology. 2002; 59: 835-838.
3. Kupeli B, Irkilata L, Gurocak S, Tunc L, Kirac M, Karaoglan U, Bozkirli I: Does tamsulosin enhance lower ureteral stone clearance with or without shock wave lithotripsy? Urology. 2004; 64: 1111-1115.

Dr. Margaret S. Pearle
Associate Professor of Urology
University of Texas Southwestern Med Ctr
Dallas, Texas, USA