Introduction
Minor surgical procedures are occasionally necessary for patients who have either a known sensitivity to procaine or who obtain little or no anesthesia from it. It was felt that a substitute drug of a different chemical structure would be of definite value. One of the physiologic properties of the antihistamines is that of local anesthesia.1 It was therefore decided to proceed with a clinical investigation of one of them, diphenhydramine hydrochloride (Benadryl) as a local anesthetic.
Review of the Literature
Rosenthal and Minard2 noticed in 1939 that thymoxyethyldiethylamine produced local anesthesia to the same extent as but of longer duration than 1% procaine (Novocaine) when injected intracutaneously or applied locally to the denuded skin in 0.5% concentration. Burchell and Varco3 noted that blebs produced in the human skin by the intracutaneous injection of either thymoxyethyldiethylamine or N′ethyl-N′-diethylaminoethylaniline were anesthetic only over