Comparison of the vasoactivity of amide and ester local anaesthetics. An intradermal study.

The vascular effects and duration of action of two ester-linked local anaesthetics, procaine and amethocaine, and four amide-linked local anaesthetics, cinchocaine, lignocaine, mepivacaine and prilocaine, were investigated in 10 volunteers by intradermal injection using a double-blind technique. Procaine and amethocaine produced marked vasodilatation; weal formation was observed at 80% of the amethocaine injection sites. Mepivacaine had a marked vasoconstrictor effect; the other three agents produced more variable vasoactivity. Duration of action was concentration-dependent for all six drugs, the slopes of the log dose--duration plots reflecting the observed vasoactivity.