An investigation in man into the relative potency of lignocaine, bupivacaine and etidocaine.

The relative potency of lignocaine, bupivacaine and etidocaine was estimated by forearm skin weals in four volunteers. Potency was estimated as the time to half-recovery of a sharp sensation in response to a needle-prick. The increase in duration of action with increased concentration was greater for bupivacaine and etidocaine as compared with lignocaine. At the same concentrations, bupivacaine had a longer duration of action than etidocaine. However, etidocaine 1% had a longer duration of action than bupivacaine 0.5%.