Dextromethorphan attenuation of postoperative pain and primary and secondary thermal hyperalgesia.
OBJECTIVE
To determine the effect of 90 mg dextromethorphan (DM) p.o. vs placebo 90 min preoperatively, on the immediate and delayed postoperative course.


METHODS
Thirty patients undergoing laparoscopic cholecystectomy or inguinal hernioplasty under general anesthesia were studied. Half (DM) received 90 mg dextromethorphan and half received placebo 90 min before anesthesia. Intravenous Patient Controlled Aanalgesia with morphine was available for two hours within a six-hour observation period; 75 mg diclofenac i.m. prn was given later in PACU and on-ward (24 hr). Pain was assessed using the visual analogue scales. Thermal thresholds for cold and hot sensation and for pain (by limit method) were evaluated at the site of skin incision (primary-) and distantly (secondary hyperalgesia). Von Frey filaments were applied testing touch sensation. Sedation level and morphine consumption were also assessed in PACU.


RESULTS
Demographic, surgical and perioperative parameters were similar; no untoward effects were encountered. Pain intensity and sedation were lower, and the feeling of well-being was greater, in the DM patients: one vs five (median), two vs five, five vs two, respectively, P <0.01 (90 min time-point). Thermal application revealed absence of primary and secondary hyperalgesia only in the DM patients; von Frey filaments induced similar pain sensation in both groups. Mean morphine/group, morphine/weight and diclofenac injection rates were approximately 55% lower in the DM group: 2.1 +/- 1.2 (SD) vs 4.7 +/- 2.3, 0.03 +/- 0.02 vs 0.07 +/- 0.03, 1.0 +/- 0.3 vs 2.4 +/- 0.2, respectively, P <0.01.


CONCLUSIONS
Compared with placebo, DM enabled reduction of postoperative analgesics consumption, improved well-being, and reduced sedation, pain intensity and primary and secondary thermal hyperalgesia.
Weinbroum
A A
AA
Post-Anesthesia Care Unit, Tel Aviv Sourasky Medical Center, and the Sackler Faculty of Medicine Tel Aviv University, Israel. draviw@tasmc.health.gov.il
Gorodezky
A
A
Niv
D
D
Ben-Abraham
R
R
Rudick
V
V
Szold
A
A
D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D017081:Cholecystectomy, Laparoscopic; D018592:Cross-Over Studies; D003915:Dextromethorphan / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006552:Hernia, Inguinal / Q000601:surgery; D006358:Hot Temperature; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D010149:Postoperative Pain / Q000517:prevention & control*; D011312:Pressure; D011446:Prospective Studies
D000701:Analgesics, Opioid; D003915:Dextromethorphan; D009020:Morphine