The effects of gabapentin on acute and chronic pain after inguinal herniorrhaphy

To find out whether preoperative gabapentin use had a favourable effect on long-term postoperative pain in patients undergoing inguinal herniorrhaphy.

Sixty male patients--aged 20-40 years--who were scheduled for unilateral inguinal herniorrhaphy under spinal anaesthesia were included in this prospective, randomized, double-blind study. The patients were randomly allocated to two groups: the gabapentin group (n=30) received single-dose 1.2 g oral gabapentin 1 h before surgery, and the placebo group received a placebo capsule instead. Spinal anaesthesia was performed with heavy bupivacaine, and all operations were performed by the same surgeon with the same technique. Postoperative analgesia was evaluated during sitting and lying with a visual analogue scale. Assessment of postoperative pain at 1, 3 and 6 months was carried out with an 11-point numerical rating scale; 0 indicating 'no pain' and 10 indicating 'worst pain imaginable'. Patients who had numerical rating scale scores of more than 0 were further evaluated with regard to the impact of pain on their daily activities.

When compared with the placebo group, the gabapentin group displayed significantly lower visual analogue scale scores (lying and sitting) and total tramadol consumption at 8, 12, 16, 20 and 24 h after surgery (P<0.05) and higher postoperative patient satisfaction scores (P<0.05). Numerical rating scale scores at 1, 3 and 6 months after surgery were lower in the gabapentin group than in the placebo group (P<0.05). The number of patients whose daily activities were adversely affected by pain was smaller in the gabapentin group at the first month; however, the two groups were found to be similar at 3 and 6 months.

We conclude that preoperative single-dose gabapentin decreases the intensity of acute postoperative pain, tramadol consumption and the incidence and intensity of pain in the first 6 months after inguinal herniorrhaphy.