[Efficacy of EMLA cream, effect of time and place of application]

To evaluate the anesthetic efficacy of EMLA cream for alleviating pain associated with puncture and pressure in areas where venous catheters are normally inserted.

We performed a prospective, double blind study in 38 volunteers between 25 and 36 years of age, after obtaining informed consent. A 1.5 g dose of EMLA cream was applied to three sites on each patient: the back of the hand, the antecubital fossa and the side of the neck. Placebo cream with similar characteristics was applied to contralateral sites. Pain was evaluated on a visual analog scale (VAS, 0-10). Tactile sensitivity was assessed on a four-point scale (0 = no sensation; 1 = slight sensation; 2 = moderate, and 3 = strong). An analysis of variance study was performed to compare baseline scores to results over time, and placebo results to EMLA scores for each test site.

The assessment of response to puncture and pressure gradually decreased over time for the sites where EMLA cream was applied, but not for the areas where placebo was applied.

The efficacy of EMLA cream varies demonstrably depending on type of stimulus, site of application and time since application.