Vascular response of human skin after analgesia with EMLA cream.

We investigated vascular responses after cutaneous application of EMLA cream (a eutectic mixture of lignocaine and prilocaine) by skin reflectance spectroscopy and laser Doppler blood flowmetry. In healthy subjects, EMLA cream produced a biphasic vascular response with an initial vasoconstriction, maximal after 1.5 h of application. After prolonged application (greater than 3 h, vasodilatation occurred, presumably because of a smooth muscle relaxant effect of the analgesics. Vasoconstriction was also observed initially with two non-EMLA creams applied under occlusion, whereas the occlusive plastic film alone did not alter the vascular state. Thus late vasodilatation was unique to EMLA cream.