LOCAL-ANESTHETIC EFFECT OF TRAMADOL, METOCLOPRAMIDE, AND LIDOCAINE FOLLOWING INTRADERMAL INJECTION

Background and Objectives. We observed clinically that tramadol and me toclopramide appear to have local anesthetic action. Tramadol is a cen tral-acting analgesic. Metoclopramide is a commonly used antiemetic. T he local anesthetic effect of tramadol in reducing propofol injection pain has never been mentioned, although it was speculated with metoclo pramide. Methods. We conducted a double-blind, placebo-controlled stud y by injecting tramadol or metoclopramide intradermally in 10 healthy volunteers (5 men, 5 women; age 25-56 years). Each subject received 0. 5 mt of four solutions in random order on the volar side of the forear m. These solutions were 25 mg tramadol, 5 mg metoclopramide, 5 mg lido caine, and 0.5 mt normal saline. Pain on injections and the degree of local anesthesia (tested by pinprick, light touch, and cold) at each s ite was reported on a 0-3 scale at designed time intervals. Results. L ike 1% lidocaine, tramadol and metoclopramide demonstrated loss of sen sation for pinprick, light touch, and fold for 15 minutes after intrad ermal injection (P < .01). Conclusions. Intradermal tramadol or metocl opramide can produce local anesthetic effect.