Effect of Intravenously Administered Dexmedetomidine on Pain After Laparoscopic Tubal Ligation

Ninety-six women undergoing laparoscopic tubal ligation were randomized to receive intravenously either 0.2 or 0.4 microgram/kg of dexmedetomidine, 60 micrograms/kg of oxycodone, or 250 micrograms/kg of diclofenac for postoperative pain in a double-blind study design. The study drugs were administered in the recovery room for moderate or severe pain and were repeated until pain subsided or disappeared. In the group receiving diclofenac, 83% of the patients required analgesic supplementation with morphine. This contrasted (P less than 0.01) with 33% of the patients receiving either oxycodone or the higher dose of dexmedetomidine. After the first dose of oxycodone was injected, the visual analogue scale for pain (0%-100%) was reduced from 58% to 33%, whereas corresponding pain relief was only achieved after the third injection of 0.4 microgram/kg of dexmedetomidine. Repeated doses of 0.2 microgram/kg of diclofenac or dexmedetomidine did not reduce the visual analogue scale value by more than 17%. More sedation was seen with the higher dose of dexmedetomidine than with either diclofenac or oxycodone (P less than 0.001). Both doses of dexmedetomidine decreased heart rate when compared with diclofenac (P less than 0.001). In the group given 0.4 microgram/kg of dexmedetomidine, 33% of the patients required atropine for bradycardia. The authors conclude that after laparoscopic tubal ligation, intravenously administered dexmedetomidine relieves pain and reduces opioid drug requirement but is attended by sedation and a high incidence of bradycardia.