Plasma levels of lignocaine after peri-oral injections of two different concentrations.

Volunteer subjects received 50 mg of lignocaine solution as a maxillary infiltration injection, one one occasion as 1% solution and on another as 5% solution. The plasma levels of lignocaine were measured over a two-hour period and similar concentrations were achieved from both solutions, although the larger volumes of the more dilute solution gave slightly higher results, probably reaching toxic levels in one case. The injection of the higher concentration did not produce particularly high plasma levels of lignocaine.