Efficacy of pre- and postoperative oral dextromethorphan for reduction of intra- and 24-hour postoperative morphine consumption for transabdominal hysterectomy.
OBJECTIVE
We studied the effect of dextromethorphan (DEX), an N-methyl-D-aspartate receptor antagonist, on analgesic consumption and pain scores after abdominal hysterectomy. We aimed to compare the analgesic effectiveness and incidence of adverse side effects of oral DEX with placebo (P).


METHODS
This was a double-blinded, randomized, placebo-controlled study.


METHODS
One hundred patients were randomized to two groups. Group DEX was given 30-mg tablets of oral DEX with their premedication and three more times in the first 24 hours after surgery. Group P received the placebo following the same schedule. Postoperative analgesic requirements were assessed using a patient-controlled analgesia system. Pain was assessed at rest using a visual analogue scale in the post-anesthetic care unit (PACU), 6 and 24 hours after surgery.


RESULTS
Mean pain scores were significantly lower at the PACU (62.6 vs 75.7) as was the mean sum of all resting pain scores (144.5 vs 173.1). Mean morphine consumption was greatest in the DEX group (35.1 vs 33.0 mg; P < 0.05). The sedation scores, postoperative analgesic requirements, and incidence of side effects were similar between the P and DEX groups as were the mean pain scores.


CONCLUSIONS
During PACU, however, there were two differences between the DEX and placebo groups: 1) a lower pain score at PACU; and 2) a prolonged time to the first use of morphine at PACU in the DEX group as compared with the placebo group. A low-dose DEX had a weaker though still measurable effect in this clinical trial compared with trials using higher doses.
Department of Anesthesiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. warcha@kku.ac.th
Waraporn
W
Chau-In
Busabong
B
Sukmuan
Kriengsak
K
Ngamsangsirisapt
Winita
W
Jirarareungsak
D015746:Abdominal Pain / Q000188:drug therapy / Q000209:etiology; D000284:Administration, Oral; D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D003915:Dextromethorphan / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007044:Hysterectomy / Q000009:adverse effects; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage*; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy*; D010919:Placebos; D011182:Postoperative Care / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D010919:Placebos; D003915:Dextromethorphan; D009020:Morphine