Study of the effect of oral gabapentin used as preemptive analgesia to attenuate post-operative pain in patients undergoing abdominal surgery under general anesthesia

Aims: To study the effect of oral gabapentin used as preemptive analgesia to attenuate post operative pain in patients undergoing abdominal surgery under general anesthesia.

Materials and methods: In a randomized double blind study, 60 patients were divided into two groups. Group A received 600mg gabapentin and group B oral received placebo 1 h prior to surgery. Anesthesia was induced with Propofol 2 mg/kg and Vecuronium 0.1mg/kg and maintained with 60% N(2)O in O(2) and Vecuronium 0.02 mg/kg. All cases were given Fentanyl 2µg/kg as pre medication and a repeat dose 1µg/kg at the end of the first hour. Assessment of post-operative pain was made with the visual analog score (VAS) at extubation (0 h), 2, 4, 6, 12, and 24 h post-operatively. Post-operative analgesia was provided with intravenous Tramadol. The first dose was given in the Post Anesthesia Care Unit as 2mg/kg, and repeated at 8 and 16 h. Rescue analgesia was given with Diclofenac 1.5mg/kg, slow intravenous. The number of doses of rescue analgesia in both the groups was noted.

Results: The VAS scores at 0, 2, 4, 6, 12, and 24 h were 1.9 vs. 2.4 (P=0.002), 2.3 vs. 3.0 (P=0.000), 3.2 vs. 3.7 (P=0.006), 2.9 vs. 4.4 (P=0.000), 3.6 vs. 4.6 (P=0.000), and 3.7 vs.4.6 (P=0.000), respectively. Numbers of patients requiring rescue analgesia with Diclofenac were 3 vs. 14 (P=0.004).

Conclusion: A single oral dose of gabapentin given pre-operatively enhanced the analgesic effect of Tramadol as it also reduced the requirement of rescue analgesia with Diclofenac.