title: Local anesthetic effect of tramadol, metoclopramide, and lidocaine following intradermal injection.
abstract: OBJECTIVE
  We observed clinically that tramadol and metoclopramide appear to have local anesthetic action. Tramadol is a central-acting analgesic. Metoclopramide is a commonly used antiemetic. The local anesthetic effect of tramadol in reducing propofol injection pain has never been mentioned, although it was speculated with metoclopramide.
  
  
  METHODS
  We conducted a double-blind, placebo-controlled study by injecting tramadol or metoclopramide intradermally in 10 healthy volunteers (5 men, 5 women; age 25-56 years). Each subject received 0.5 mL of four solutions in random order on the volar side of the forearm. These solutions were 25 mg tramadol, 5 mg metoclopramide, 5 mg lidocaine, and 0.5 mL normal saline. Pain on injections and the degree of local anesthesia (tested by pinprick, light touch, and cold) at each site was reported on a 0-3 scale at designed time intervals.
  
  
  RESULTS
  Like 1% lidocaine, tramadol and metoclopramide demonstrated loss of sensation for pinprick, light touch, and cold for 15 minutes after intradermal injection (P < .01 ).
  
  
  CONCLUSIONS
  Intradermal tramadol or metoclopramide can produce local anesthetic effect.
authors.affiliation: Department of Anesthesia, Show-Chwan Memorial Hospital, Changhua, Taiwan, ROC.
authors.forename: W W
authors.initials: WW
authors.lastname: Pang
authors.forename: M S
authors.initials: MS
authors.lastname: Mok
authors.forename: D P
authors.initials: DP
authors.lastname: Chang
authors.forename: M H
authors.initials: MH
authors.lastname: Huang
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000494:pharmacology; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000494:pharmacology*; D000932:Antiemetics / Q000494:pharmacology; D003080:Cold Temperature; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007271:Injections, Intradermal / Q000009:adverse effects; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology*; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D010919:Placebos; D012677:Sensation / Q000187:drug effects; D012867:Skin / Q000187:drug effects; D014110:Touch / Q000187:drug effects; D014147:Tramadol / Q000494:pharmacology*
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000932:Antiemetics; D010919:Placebos; D014147:Tramadol; D008012:Lidocaine; D008787:Metoclopramide