Lumbar epidural anesthesia with 20 ml of either 3% 2-chloroprocaine (C), 1.5% lidocaine (L), or 1.5% mepivacaine (M) with epinephrine was studied in 84 outpatients undergoing surgery (extracorporeal shock wave lithotripsy (ESWL]. The average duration of the procedure was 31.9 minutes. The total duration of sensory anesthesia was 133 +/- 28 minutes (C), 182 +/- 38 (L), and 247 +/- 42 (M) (p less than 0.05). Times to discharge were 269 +/- 62 minutes (C), 284 +/- 62 (L), and 357 +/- 71 (M). The time to discharge with M, almost six hours, was significantly longer than with C or L. There was a trend to an increasing rate of unplanned overnight hospital admission with increasing duration of the local anesthetic drug employed. Continuous epidural anesthesia with C, L or M appears safe and effective for outpatient surgical procedures such as ESWL. In contrast to previous understanding, mepivacaine produces significantly longer anesthesia and recovery times and may not be optimal for outpatient epidural use.