Pharmacokinetics of interpleural bupivacaine in patients undergoing cholecystectomy.

Arterial and venous plasma concentrations of bupivacaine were measured following interpleural administration of 20 ml of 0.5% solution with adrenaline in patients undergoing cholecystectomy. Mean maximum arterial and venous concentrations in eight of 11 patients were 1.90 (SD 0.36) and 1.65 (0.48) mg litre-1 and occurred at 22 (10) min and 25 (10) min, respectively. An arteriovenous difference for bupivacaine of approximately 20% was noted during the first 45-60 min after administration. Mean systemic venous plasma clearance (0.15 (0.08) litre h-1 kg-1) was less and the mean elimination half-life (6.85 (2.29) h) and mean body residence time (9.99 (3.00) h) were longer than reported previously for interpleural bupivacaine--possibly because of continued slow absorption of the drug from its absorption site.