Gabapentin attenuates late but not acute pain after abdominal hysterectomy

Background and objective: Gabapentin has been suggested to decrease acute postoperative pain. We evaluated the effect of gabapentin on pain after abdominal hysterectomy. Methods: Sixty patients scheduled for abdominal hysterectomy were randomized to receive orally gabapentin 400 mg 6 hourly or placebo. Treatment started 18 h preoperatively and continued for 5 postoperative days. Pain (visual analogue score) and consumption of morphine for 48 h and of oral paracetamol/codeine were recorded after 2, 4, 8, 24 and 48 h and on days 3-5 postoperatively. After 1 month, patients were interviewed by phone for pain, and analgesic intake after hospital discharge. Results: Morphine consumption (mean ± SD) was 35 ± 15.7 mg in the control and 28 ± 12.1 mg in the gabapentin group (P = 0.21). Median number (range) of paracetamol 500 mg/codeine 30 mg tablets taken during days 3-5 was 1.0 (0-6) in the control and 2.0 (0-9) in the gabapentin group (P = 0.35). The visual analogue scores at rest and after cough did not differ between the two groups (F = 0.92, df = 1, P = 0.34 and F = 0.56, df = 1, P = 0.46, respectively). One month after surgery, 22/27 (81%) of the control group and 9/25 (36%) of the gabapentin group reported pain in the surgical area (χ² = 11.15, P = 0.002), while 11/27 (41%) of controls and 7/25 (28%) of gabapentin patients consumed analgesics for pain (χ² = 0.93, P = 0.39). The intensity of pain was decreased in the gabapentin group (χ² = 12.6, P = 0.003). Conclusions: Gabapentin has no effect on immediate pain after abdominal hysterectomy but decreases pain 1 month postoperatively.