Topical anaesthesia for extracorporeal shock wave lithotripsy.

We have investigated 60 patients in a prospective double-blind, placebo-controlled study to assess the efficacy of EMLA (Eutectic Mixture of Local Anaesthetics) cream to provide analgesia during extracorporeal shock wave lithotripsy (ESWL) with a second generation lithotriptor. Before operation, EMLA or placebo cream was applied to the patient's back at the anticipated shock head-skin interface. During the procedure increments of fentanyl 0.5 micrograms kg-1 were given i.v. on patient demand. There was no significant difference (P = 0.83) in the dose of fentanyl given to each group. We cannot recommend, therefore, the use of EMLA cream as an analgesic during ESWL with a second generation lithotriptor.