The dosage of dilute lignocaine for the infiltration technique of local analgesia

Abstract

The maximum dose of plain lignocaine is the subject of debate. The manufacturers recommend 200 mg in the 'adult' and clinicians often use up to 500 mg or more. One way of settling the issue is to determine serum concentrations of free lignocaine, in the absence of which recommendations are based on clinical experience. For the infiltration technique of local analgesia 500 mg is a safe maximum for plain lignocaine and 670 mg with adrenaline. These higher dosages are recommended only for dilute solutions such as 0.4% and 0.5% lignocaine. The 0.2% solution can permit the use of even higher dosages. A discussion of serum concentrations indicates that these recommendations are within acceptable limits. Concentrated 1% and 2% solutions should not be used for the infiltration technique.