Answer:
EMLA (Eutectic Mixture of Local Analgesia) is a topical anesthetic, usually a mixture of lidocaine and prilocaine, which can provide local anesthesia for superficial skin procedures including venous cannulation, skin grafting, and wart removal. Studies show that the depth of anesthesia is related to the duration of application. A maximal depth of 5 mm of anesthesia to needle insertion was found after application of EMLA for 90 min followed by a 30 min waiting period. Effects usually wear off within 3-4 hrs of initial application. The prolonged period of onset (1-2 hrs) usually limits EMLA's usefulness.