Duration of intradermal anaesthesia with mixtures of bupivacaine and lidocaine

In a double-blind trial on 20 human volunteers, the duration of intradermal anaesthesia with bupivacaine 0.25 per cent was compared with duration with a mixture of bupivacaine 0.25 per cent and carbonated lidocaine 1.0 per cent and with a mixture of bupivacaine 0.25 per cent and lidocaine hydrochloride 1.0 per cent. The duration of intradermal anaesthesia produced by bupivacaine mixed with carbonated lidocaine was 114 +/- 56 (mean +/- 1 SD) minutes and was not significantly shorter than the duration of the bupivacaine alone, at 125 +/- 70 minutes, or duration with the mixture of bupivacaine and lidocaine hydrochloride, which was 112 +/- 41 minutes. These results indicate that the mixture of bupivacaine with either carbonated lidocaine or lidocaine hydrochloride may be used for local anaesthesia without significant shortening of the duration of action.