Opioid analgesia in extracorporeal shock wave lithotripsy: fentanyl versus alfentanil.

More than 1,600 patients have been treated by extracorporeal shock wave lithotripsy (ESWL) under fentanyl analgesia without any complications or severe side-effects. As secondary respiratory depression is still under discussion, we investigated the value of alfentanil--a short-term acting opioid--with special interest in its efficacy and side-effects. Neither fentanyl nor alfentanil significantly influenced blood pressure, respiratory rate and blood gases. With regard to minor side-effects and patient's acceptance, alfentanil analgesia should be preferred during ESWL treatment.