Dextromethorphan and pain after total abdominal hysterectomy

Area of Science:

• Anesthesiology
• Pharmacology
• Pain Management

Background:

• N-methyl-D-aspartate (NMDA) receptor antagonists, like dextromethorphan, show potential in managing pain.
• Previous research suggests dextromethorphan can inhibit cutaneous secondary hyperalgesia following tissue trauma.

Purpose of the Study:

• To evaluate the efficacy of dextromethorphan in preventing or reducing postoperative pain and secondary hyperalgesia.
• To assess the impact of dextromethorphan on pain perception and opioid consumption in patients undergoing total abdominal hysterectomy.

Main Methods:

• A randomized, double-blind, placebo-controlled trial involving 60 patients (ASA I-II) undergoing total abdominal hysterectomy.
• Patients received either dextromethorphan (27 mg capsules) or a placebo, with specific dosing schedules before and after surgery.
• Pain was assessed using Visual Analogue Scales (VAS) at rest, on coughing, and on sitting up at 24 and 48 hours post-operation. Secondary hyperalgesia was evaluated using von Frey hairs. Morphine consumption via patient-controlled analgesia (PCA) was also recorded.

Main Results:

• No significant differences were observed in Visual Analogue Scale (VAS) pain scores between the dextromethorphan and placebo groups at 24 and 48 hours.
• Secondary hyperalgesia was present in both groups, with no statistically significant difference between dextromethorphan and placebo.
• Morphine consumption from patient-controlled analgesia (PCA) devices did not differ significantly between the two groups. VAS scores at 1 month also showed no difference.

Conclusions:

• Dextromethorphan administration did not significantly reduce postoperative pain or the development of secondary hyperalgesia in patients undergoing total abdominal hysterectomy.
• The study suggests that dextromethorphan, at the tested dosage and regimen, may not be effective for managing acute postoperative pain and hyperalgesia in this surgical context.
• Further research may be needed to explore alternative NMDA receptor antagonists or different therapeutic strategies for managing post-surgical pain.