As compared with lidocaine, mepivacaine 5 mg kg –1 providedbetter intraoperative analgesia with no adverse effects on releaseof the tourniquet. Moreover this finding is supported by plasmaconcentrations of the drugs that were comparable 5 min afterdeflation ( () µg ml –1 for lidocaine () µg ml –1 for mepivacaine), whilst plasmaconcentrations of lidocaine decreased significantly ( ()µg ml –1 ) at 60 min as opposed to plasma concentrationsof mepivacaine that did not vary ( () µg ml –1 ).The observation of similar plasma concentrations of both anaestheticagents despite the use of almost double concentrations of mepivacainemay be explained by the vascular effects of mepivacaine (vasoconstriction)in IVRA 19 and a much more sustained release to the systemiccirculation as compared with the predominatly vasodilatory effectsof lidocaine. 20 Therefore, toxic plasma concentrations of mepivacaineare not reached rapidly as opposed to lidocaine 3 mg kg –1 when adverse events may appear within the first minute aftertourniquet release as reported by Simon and associates. 8 Onthe other hand, the relatively prolonged nature of the increasein systemic mepivacaine concentrations might produce longerterm psychometric effects. However, we did not examine thisin our study.