Splanchnic elimination and systemic toxicity of bupivacaine and etidocaine in man.

Fifteen healthy young volunteers were studied in connection with an intravenous infusion of a local anaesthetic agent. Seven received bupivacaine and eight etidocaine in a dose rate of 2 mg.min-1 over a period of 150 min. The hepatic blood flow and arterial-hepatic venous differences of the two drugs were measured. The estimated hepatic blood flow increased during the infusion of both drugs. While the splanchnic extraction ratio decreased during infusion of bupivacaine to 0.41 +/- 0.13, the same variable did not change (0.76 +/- 0.07) when etidocaine was infused. After 150 min infusion, the splanchnic clearance of bupivacaine and etidocaine was 0.76 +/- 0.27 and 1.32 +/- 0.21 1.min-1, respectively. Slight symptoms of central nervous toxicity were noted towards the end of the bupivacaine infusion, while no such symptoms appeared with etidocaine. A comparison between earlier published data on the blocking properties and the disposition pharmacokinetics of the two drugs shows that etidocaine is likely to confer a clinical advantage over bupivacaine as regards toxicity.