A randomized trial of adjuvant tamsulosin as a medical expulsive therapy for renal stones after shock wave lithotripsy.

Adjuvant medical expulsive therapy (MET) for shock wave lithotripsy (SWL) is controversial. With limited use of the computed tomography (CT), the stone free rate (SFR) become overestimated. Herein we evaluate tamsulosin post-SWL for renal stone using the CT to assess SFR. A randomized controlled trial (NCT05032287) was carried out for renal stone patients amenable for SWL. Patients were allocated after 1st session of SWL to receive tamsulosin 0.4 mg or placebo once daily from the 1st day of SWL and for 3-months or becoming stone free. The primary outcome was SFR, defined by presence of residual fragments (RF) ≤ 3 mm (3C-SFR). The 3C-SFR were 73.8% and 59.6% in tamsulosin and placebo groups, respectively (p = 0.03). The median (IQR) pain scores were 3 (3, 5) and 5 (3, 6) in tamsulosin and placebo groups, respectively (p = 0.04), However, the post-SWL complication and add-on analgesia needed showed no significance differences between groups. The median time for stone free were 30 days (95% CI: 27.29-32.71) in tamsulosin arm, and 36 days (95% CI: 31.01-40.99) in placebo arm, HR = 1.42 (95% CI: 1.02-1.98). Tamsulosin has more reversible adverse effect, compared to placebo (p = 0.03). In our study, the use of tamsulosin as MET following SWL facilitates expulsion of retained residual fragments. Tamsulosin shortens time to reach stone free, decreases pain scores. However, tamsulosin does not affect the add-on IV analgesics and have more reversible adverse effect, compared to placebo.