The history and progress of local anesthesia: multiple approaches to elongate the action.

Analgesia and temporary inhibition of motor activity without interfering with central nervous function have been the essential merits of local anesthesia. Local anesthetics originated from cocaine have played a major role in local analgesia. However, the relatively short duration of action of local anesthetics has been a concern in intra- and post-operative analgesia. From the early age of modern local anesthesia, physicians and medical scientists had been struggling to control the active duration of local anesthetics. Such approach includes: development of long-acting local anesthetics, with physical tourniquet techniques, co-administration of other medicines such as vaso-constrictive agents or analgesics, development of mechanical devices to continuously or intermittently administer local anesthetics, and utilization of pharmaceutical drug delivery systems. In this review, the historical sequence of studies that have been performed in an effort to elongate the action of local anesthetics is presented, referring to epoch-making medical and scientific studies.