title: Premedication with dextromethorphan provides posthemorrhoidectomy pain relief.
abstract: OBJECTIVE
  Previous studies have shown that N-methyl-D-aspartate receptor antagonists provide a preemptive analgesic effect in humans. This study was designed to examine whether premedication with dextromethorphan, an N-methyl-D-aspartate antagonist, also provided a preemptive analgesic effect that improved postoperative pain management.
  
  
  METHODS
  Sixty patients who were American Society of Anesthesiologists status I and II scheduled for hemorrhoidectomy (modified Whitehead procedure) were included in the study. Patients were randomly assigned to the control and study groups. For the control group patients received chlorpheniramine maleate (20 mg), a component of the injection form of dextromethorphan, intramuscular injection 30 minutes before skin incision. In the study group dextromethorphan 40 mg containing 20 mg chlorpheniramine maleate (intramuscular) was given as premedication 30 minutes before skin incision. Pethidine (1 mg/kg, intramuscular) was given for pain relief as required postoperatively. The time to first pethidine injection, total pethidine consumption, worst pain score, and pethidine-related side effects were recorded for 48 hours postoperatively.
  
  
  RESULTS
  The times to first pethidine injection (mean +/- standard error of the mean) were 5.2 +/- 3 and 19.6 +/- 6 hours in the control and study groups, respectively. Total pethidine consumption was 140 +/- 11.3 and 63.5 +/- 11.8 mg in the control and study groups. The worst visual analog scale pain scores were 7.4 +/- 0.2 and 5.6 +/- 0.3 in the control and study groups during the two-day observation. The numbers of patients who required pethidine injection were 29 and 20 in the control and study groups, respectively. Two patients suffered pethidine-related side effects, such as nausea, vomiting, dizziness, and headache, in the control group, and no patient complained of any side effect in the study group.
  
  
  CONCLUSIONS
  We found that dextromethorphan premedication provided a preemptive analgesic effect, thus producing reduced postoperative pain and pethidine requirement and improved recovery from hemorrhoidectomy.
authors.affiliation: Section of Anesthesia, Armed Forces Sung-Shang Hospital, Taipei, Taiwan, Republic of China.
authors.forename: S T
authors.initials: ST
authors.lastname: Liu
authors.forename: C T
authors.initials: CT
authors.lastname: Wu
authors.forename: C C
authors.initials: CC
authors.lastname: Yeh
authors.forename: S T
authors.initials: ST
authors.lastname: Ho
authors.forename: C S
authors.initials: CS
authors.lastname: Wong
authors.forename: S W
authors.initials: SW
authors.lastname: Jao
authors.forename: C C
authors.initials: CC
authors.lastname: Wu
authors.forename: J C
authors.initials: JC
authors.lastname: Kang
mesh_terms: D000328:Adult; D003915:Dextromethorphan / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D018691:Excitatory Amino Acid Antagonists / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006484:Hemorrhoids / Q000601:surgery*; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D011183:Postoperative Complications / Q000517:prevention & control; D011300:Preoperative Care
chemical_list: D018691:Excitatory Amino Acid Antagonists; D003915:Dextromethorphan