Effect of chronic bupivacaine infusion on seizure threshold to bupivacaine

Thirty rats were pretreated with a continuous infusion of bupivacaine or placebo. On the fourth day the acute seizure threshold to bupivacaine was determined for both groups. The seizure dose, blood and brain concentration of bupivacaine showed no difference between the groups. The tachyphylaxis seen clinically when bupivacaine is used for a regional nerve blockade does not seem to evolve for the CNS-effects.