Cardiovascular and subjective central nervous system effects of long-acting local anaesthetics in man.

Intravenous infusions of etiodocaine 50, 75 and 100 mg and bupivacaine 75 mg were carried out over ten minutes in healthy young adult males. Cardiovascular sequelae were generally trivial at all doses. A collection of subjective central nervous system symptoms were described which may be regarded as early warning of impending local anaesthetic toxicity. Plasma concentrations of etidocaine were proportional to dose and ranged from 2 micrograms/ml to 5 micrograms/ml at the termination of the infusion. Plasma concentrations of bupivacaine were similar to those from the same dose of etidocaine but declined more slowly on cessation of infusion.