Maximum recommended doses of lignocaine are not toxic.

Abstract

The maximum recommended doses of lignocaine are frequently exceeded in clinical practice as some blocks may need more lignocaine to produce adequate anaesthesia. We have examined the success rate of brachial plexus block, possible toxic symptoms after a dose of lignocaine 900 mg with adrenaline, and the maximum plasma concentration of lignocaine produced in 17 adult patients. In all patients, the block was excellent and no toxic symptoms were encountered. The highest mean lignocaine plasma concentration was 2.9 micrograms ml-1 45 min after the block. We conclude that in brachial plexus block, the dose of lignocaine with adrenaline can be as high as 900 mg without fear of toxic symptoms.