This study was undertaken to evaluate the effects of patient-controlled analgesia (PCA) with alfentanil and compare with intermittent IV bolus administration for ESWL. Thirty (ASA I-II) patients undergoing ESWL were divided in two groups. Group I PCA received a loading dose (10 µg/kg IV) and maintenance close (5 µg/kg IV) of alfentanil with a lock out of 10 minutes. Group II received intermittent IV bolus alfentanil (30 µg/kg) initially then 1 mg as necessary to relieve pain. Vital signs; HR, SAP, DAP, RR, SaO2; Visual analogue pain scores (VAS) and Comfort Scores were obtained in every 15 minutes during lithotripsy. Time to recovery and discharge, acceptability scores and amount of alfentanil received were determined in both group. There were no significantly differences between the two groups with demographic values, duration of ESWL and vital signs. VAS and comfort scores were insignificantly lower in PCA group (p>0.05). No adverse effects were obtained in both group. Time to recovery and discharge were significantly shorter and alfentanil requirement was significantly lower in PCA group (p<0.001). PCA with alfentanil was chosen significantly acceptable technique for the patients (p<0.001). In conclusion we decided that PCA with alfentanil may be preferred for providing safe and effective analgesia during lithotripsy
