Randomized study to compare the effect of pregabalin with fixed-drug combination of pregabalin and methylcobalamin in the patients of postherpetic neuralgia

Abstract

Aim: To know the effect of adding methylcobalamin to pregabalin in patients of postherpetic neuralgia (PHN) and also to compare the side effects of pregabalin alone and fixed-drug combination (FDC) of pregabalin and methylcobalamin. Materials and Methods: This was a multicenter randomized 10-month prospective study. A total of 90 patients with PHN (age and sex matched) were included. Baseline pain intensity was measured on a 10-point visual analog scale (VAS) score. Patients were randomized into two groups. Group A patients received pregabalin (75 mg) 12th hourly, whereas Group B patients were given FDC of pregabalin (75 mg) along with methylcobalamin (750 μg) 12th hourly. Thereafter, patients were assessed for the pain score at 4, 8, and 12 weeks after initiation of the treatment. The frequency and severity of adverse events were assessed. Results: Before starting medication, the average VAS score of Group A and Group B was 6.86 and 6.97, respectively. Post-medication average VAS score of Group A and Group B was found out to be 2.95 and 3.11, respectively. A significant reduction in VAS scores of both the groups was observed when compared to their respective baseline VAS scores (P < 0.001). But post-medication VAS scores of both the groups were not statistically significant (P = 0.58). Side effects such as dizziness and somnolence were observed in both the groups. This was also found out to be not statistically significant when side effects of both the groups were compared (P = 0.52). Conclusion: The result of our study shows minimal statistical difference between pregabalin alone and the FDC of pregabalin with methylcobalamin for the treatment of PHN. Patients showed improvement in pain with minimal side effects such as somnolence and dizziness in both the groups.