Pain-free venepuncture. Effect of timing of application of local anaesthetic cream.

This study was designed to assess the effect of time on the analgesic effect of a local anaesthetic cream consisting of a mixture of 5% lignocaine and prilocaine. The cream and placebo were compared in a double-blind, randomized study in 114 children aged 4-17 years, with application times of 20 minutes and longer. A regression analysis revealed no difference in analgesic effect between cream and placebo when application times were less than 60 minutes. A cusum test showed that the effect of the cream became evident at about 60 minutes. Local adverse reactions consisted mainly of transient paleness of the skin, which did not constitute any clinical problem.