Background and objectives: Analgesia and sedation are usually required during extracorporeal shock wave lithotripsy. In the present study, the recovery time and effectiveness of sedation and analgesia of dexmedetomidine me was compared with a midazolam/fentanyl combination in outpatient extracorporeal shock wave lithotripsy. Methods: Forty-nine patients scheduled for outpatient extracorporeal shock wave lithotripsy were randomly assigned to two groups: a dex group (n = 25; dexmedetomidine 1 mu g kg(-1) loading dose followed by dexmedetomidine 0.2 mu g kg(-1) h(-1)) and a control group (n = 24; midazolam 0.05 mg kg(-1) and fentanyl 1 mu g k(-1) h(-1)) and a control group (n = 24; midazolam 1 mg), and patients' satisfaction rates were recorded. Results: The two groups were similar regarding patient characteristics and procedure-related details (P>0.05). Recovery time was significantly prolonged in the dex group when compared with the control group (116.4 +/- 39.3 vs. 50.8 +/- 19.8 min, respectively, P < 0.001). The percentage of patients requiring rescue doses of fentanyl and the applied doses were significantly higher in the dex group than in the control group (96% vs. 67%, P = 0.01; and 69.0 +/- 31.7 vs. 38.8 +/- 42.9 mu g, respectively, P = 0.007). More patients in the dex group received rescue midazolam (96% vs. 58%, P = 0.002). More patients in the control group were highly satisfied with their sedarion/analgesia (83% vs. 56%, P = 0.038). Conclusion: Dexmedetomidine was associated with a longer recovery time than a midazolam/fentanyl combination when used for sedation and analgesia during Outpatient extracorporeal shock wave lithotripsy in this study. The incidence of rescue sedative and analgesic need was also significantly higher when demedetomidine was used.