The effects of gabapentin in the treatment of neuropathic pain: a small sample randomized controlled clinical trial

Abstract

Objective To explore the efficacy and safety of gabapentin, an anticonvulsant, in the treatment of neuropathic pain (NP). Methods Eighty⁃four patients with NP were randomly allocated into 2 groups, group A (gabapentin, n = 44) and group B (carbamazepine, n = 40). The patients in group A were given gabapentin 300 mg orally only one time on the first day, twice on the second day, and started from the third day, 3 times per day until the first weekend. Since then, the dose can be gradually adjusted according to the degree of pain relief and adverse drug reactions, but the maximum dose was not more than 2400 mg/d, 3 times daily. The dose, which can relieve or eliminate pain and symptoms would be used as a maintenance dose for 8 weeks until the end of the trial. The patients in group B received carbamazepine 100 mg orally twice a day on the first day, and 3 times on the second day, continuously until the first weekend. Since then, the dose can be gradually adjusted according to the degree of pain relief and adverse drug reactions, but the maximum dose can not be given more than 800 mg/d, 3 times orally. The dose, which can relieve or eliminate pain and symptoms would also be maintained for 8 weeks until the end of the trial. Quantification of the pain severity was determined by using Visual Analog Scale (VAS) at the beginning of the study and 1, 2, 4 and 8 weeks after treatment. In the meanwhile, blood and urine routine examination, and liver and renal function tests were performed both before and after treatment. In addition, adverse drug reactions were also observed. Results Eighty⁃three patients accomplished the clinical trial. The results of VAS in group A at 1, 2, 4 and 8 weeks after therapy were all significantly decreased (P = 0.001, for all). From the second weekend of the therapy, the scores of VAS at every time point in group A were all lower than those in group B, respectively (P = 0.011, 0.001, 0.001). After 8 weeks treatment, the effective rate of gabapentin (87.50%, 35/40) was significantly higher than that of carbamazepine (67.44%, 29/43; χ2 = 4.723, P = 0.030). The ratio of adverse effects in 2 groups were not significantly different (Z = 0.324, P = 0.373), and there were no abnormal changes in blood and urine routine examination, and liver and renal function tests. Conclusion Gabapentin is safe and effective to treat NP. It is worthy of clinical application.

DOI：10.3969/j.issn.1672-6731.2010.06.008