Fentanyl versus sufentanil: plasma concentrations during continuous epidural postoperative infusion in children.

No pharmacokinetic data are available with respect to the plasma concentrations and fentanyl or sufentanil during epidural administration in children. This double-blind randomized study included 12 children (5-12 yr). Patients in group F were given an epidural loading dose of fentanyl 1.5 micrograms kg-1 and in group S sufentanil 0.6 microgram kg-1. Both groups then received a continuous epidural infusion of bupivacaine 5 mg kg-1 day-1 with either fentanyl 5 micrograms kg-1 day-1 or sufentanil 2 micrograms kg-1 day-1. An epidural PCA system was also given to the children (bolus: bupivacaine 0.2 mg kg-1 and fentanyl 0.2 microgram kg-1 or sufentanil 0.08 microgram kg-1). Maximal median concentrations of plasma (0.117-0.247 ng ml-1 for fentanyl and 0.027-0.074 ng ml-1 for sufentanil) were reached approximately 30 and 20 min respectively after the loading doses. These values were similar to those measured after 48 h.