title: Effects of preoperative use of oral dextromethorphan on postoperative need for analgesics in patients with knee arthroscopy.
abstract: BACKGROUND
  Studies have shown that N-methyl-D-aspartate receptor (NMIDA) plays an essential role in postoperative pain. It seems that use of NMDA receptor antagonists such as Dextromethorphan intensifies the analgesic effects of opioids.
  
  
  OBJECTIVE
  In this study, we evaluated the effect of preoperative administration of Dextromethorphan on postoperative pain reduction.
  
  
  METHODS
  This double blind randomized clinical trial was conducted on arthroscopic surgery candidates. Participants were randomly allocated to interventions and assigned to two groups of Dextromethorphan and placebo. In Dextromethorphan group, the patients received 1 mg/kg Dextromethorphan orally the night before the operation. Pain severity based on the visual analog scale (VAS) up to 16 hours postoperation, use of opioids, and the first request for analgesics were recorded postoperatively.
  
  
  RESULTS
  A total of 112 patients in the Dextromethorphan (n = 54) and placebo groups (n = 58) were evaluated. No significant difference was detected between the two groups for age, sex or ASA. The mean amount of opioid consumption was significantly lower in patients who received Dextromethorphan (10.7 ± 5.6 mg) compared to the placebo group (13.1 ± 5.6 mg), (P = 0.03). The mean time until the first opioid request in patients who received Dextromethorphan was longer than that in the placebo group (P = 0.01).
  
  
  CONCLUSIONS
  The study results demonstrated that preemptive use of Dextromethorphan reduced postoperative pain and opioid consumption.
authors.affiliation: Department of Anesthesiology, Rasoul Akram Medical Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Saeid Reza
authors.initials: SR
authors.lastname: Entezary
authors.affiliation: Department of Anesthesiology, Rasoul Akram Medical Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Saeedeh
authors.initials: S
authors.lastname: Farshadpour
authors.affiliation: Department of Anesthesiology, Rasoul Akram Medical Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahmood Reza
authors.initials: MR
authors.lastname: Alebouyeh
authors.affiliation: Department of Anesthesiology, Rasoul Akram Medical Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Farnad
authors.initials: F
authors.lastname: Imani
authors.affiliation: Department of Orthopedic, Faculty of Medicine, Baqiyatallah University of Medical Sciences , Tehran, Iran.
authors.forename: Mohammad Kazem
authors.initials: MK
authors.lastname: Emami Meybodi
authors.affiliation: Department of Physiology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Habibollah
authors.initials: H
authors.lastname: Yaribeygi
keywords: Analgesia; Analgesics, Opioid; Pain; Postoperative Period