PHARMACOKINETICS OF LIDOCAINE WITH EPINEPHRINE IN PIGLETS FOLLOWING EPIDURAL-ANESTHESIA

The time course of arterial plasma lidocaine concentration, following an epidural anaesthesia via the sacrococcygeal or the S4-S5 trans-sacr al approach, was studied in nine healthy piglets (7.8 +/- 1.3 weeks). Plasma lidocaine concentrations were measured for up to six hours afte r administration (5 mg/kg). Peak plasma concentration was 1.83 +/- 0.1 7 mg/l. Pharmacokinetic parameters determined from an independent comp artment model were not different from those observed after an epidural administration of lidocaine via the sacrococcygeal space in children, except for a wide variability in the time taken to reach the maximum concentration (27.3 +/- 7.4 min) and a shorter half-life of eliminatio n (82.8 +/- 7.0 min). The total body clearance of lidocaine was simila r in piglets (17.3 +/- 1.6 ml/min/kg) to that in children. The shorter half-life of elimination was therefore attributed to a smaller volume of distribution in piglets (2.0 +/- 0.2 l/kg).