The effect of pre-operative administration of gabapentin on post-operative pain relief after herniorrhaphy

BACKGROUND: Gabapentin, an anticonvulsant, recently has been suggested as an effective post-operative “analgesic” agent. The objective of the present study was to examine the analgesic effectiveness and opioid-sparing effects associated with the use of a single dose of gabapentin as a prophylactic analgesic. MATERIALS AND METHODS: In a randomized double-blinded clinical trial, 50 American Society of Anesthesiologists I and II patients with an age range of 40-60 years who were the candidate for inguinal herniorrhaphy under spinal anesthesia were randomly assigned to receive 400 mg gabapentin or placebo 2 h prior to surgery. Post-operatively, the pain was assessed on a visual analog scale (VAS) at 2, 4, 12 and 24 h at rest. Morphine 0.05 mg/kg intravenously was used to treat post-operative pain on patient's demand. Total morphine consumption in the first 24 h after surgery was also recorded. RESULTS: Patients in the gabapentin group had significantly lower VAS scores at the all-time intervals of study than those in the placebo group (P < 0.05). The total morphine consumption in the first 24 h after surgery was also significantly lower in gabapentin group than in the placebo group (0.9 ± 1.23 vs. 1.8 ± 1.5; P = 0.003). There was no significant difference between the first time of analgesic request among the two groups. CONCLUSION: In conclusion, prophylactic administration of gabapentin decreases pain scores and analgesic consumption in the first 24 h after repair of inguinal hernia.