Gabapentin versus nortriptyline in post-herpetic neuralgia patients: a randomized, double-blind clinical trial--the GONIP Trial

Abstract

Background: Gabapentin and nortriptyline have not been compared in a randomized trial in post-herpetic neuralgia (PHN). The present study was, therefore, undertaken to determine their comparative efficacy and tolerability in the treatment of post-herpetic neuralgia.

Patients and methods: The study was a randomized, double-blind, parallel-group trial of 9 weeks duration. Adult PHN patients with history of > 8 weeks of PHN pain after healing of rash, a pain intensity of at least 40 mm on a 100 mm visual analog scale at screening and at randomization, and average pain score of at least 4 on the Likert scale during the baseline week were included in the study. Gabapentin and nortriptyline were given in incremental doses at 2-weekly intervals till a maximum tolerated dose was obtained. The primary efficacy parameter was change in pain score (11-point Likert scale) from baseline to the end of the study period.

Results: 70 patients were available for intention-to-treat analysis. The average pain scores on the Likert scale were significantly reduced at the end of study in both the treatment groups with 47.6% and 42.8% reduction in pain scores in nortriptyline and gabapentin groups, respectively. Patients showed significant improvement in sleep scores in both the treatment groups nortriptyline (46.0%) and gabapentin (52.0%). The VAS and the SF-MPQ scores for pain were significantly reduced in both the groups. Gabapentin was, however, better tolerated as compared to nortriptyline.

Conclusion: Gabapentin was shown to be equally efficacious but was better tolerated compared to nortriptyline and can be considered a suitable alternative for the treatment of PHN.