Plasma lignocaine levels during transurethral prostatectomy.

It has been reported that transurethral absorption of lignocaine may cause systemic toxicity when associated with mucosal damage within the urethra. We measured the serum levels of lignocaine in 30 patients after the transurethral administration of 400 mg lignocaine gel just before transurethral prostatectomy. In 11 patients additional lignocaine was given as part of the anaesthetic induction (Group A). In 19 patients no additional lignocaine was given (Group B). Two patients in Group A and three patients in Group B also underwent Otis urethrotomy. The mean peak plasma lignocaine concentration as measured by sequential venous samples was 1424 ng/ml in Group A and 72 ng/ml in Group B. We conclude that 400 mg lignocaine gel applied endourethrally before transurethral resection of the prostate results in plasma concentrations well below the toxic levels.