A Comparison of the Properties of Lag‐43, Prilocaine and Mepivacaine in Extradural Anaesthesia

SUMMARY 0.5% LAC‐43 (Marcaine®), 2% mepivacaine (Carbocaine®) and 2% prilocaine (Citanest®), all with adrenaline 1:200,000, were compared in extradural anaesthesia in a controlled study. The anaesthesia is illustrated graphically as a surface (segment‐minutes). This makes it possible to compare the results with those of other investigators as regards time of onset, duration and spread of analgesia, regardless of how these have been defined. The duration of analgesia was the only property of those investigated where significant differences between the agents were observed. The duration, defined as the time between the first and last appearance of analgesia, was, on an average, approximately 5 hours for LAC‐43 and 3 hours for mepivacaine and prilocaine. No significant side effects were observed with any of the agents. The results obtained in this investigation are strongly in favour of the use of LAC‐43 whenever a long duration of effect is required.