Dose related efficacy of gabapentin in acute herpetic neuralgia among geriatric patients

Background: Herpes zoster is an intractable painful condition, more severe in elderly patients. The pain during the first 30 days of onset is known as Acute Herpetic Neuralgia. Multiple treatments using non-steroidal anti-inflammatory drugs (NSAIDs), opioids, and tricyclic anti-depressants are available, but their side effects limit their use in geriatric patients. Gabapentin is also used in chronic neuropathic pain; however, its role in acute herpetic neuralgia is less explored. Aim : This study was aimed to determine dose related efficacy and safety of gabapentin in reducing pain of acute herpetic neuralgia in geriatric patients. Materials and Methods: In this placebo-controlled, four-week trial including 56 subjects, 42 patients received gabapentin in the dosage of 300 mg (n=15), 600 mg (n=14), and 900 mg(n=13) per day in divided doses and 14 patients received placebo within 72 hours of onset of herpes zoster. Results: Subjects receiving gabapentin had a statistically significant reduction (P<0.0001) in visual analog scale (VAS) score as compared to placebo, emphasizing the efficacy of gabapentin in the treatment of acute pain associated with herpes zoster on each assessment (weeks 1, 2, 3, and 4). Gabapentin in doses of 600 mg/day and 900 mg/day was better than 300 mg/day in each visit. However, no difference was observed between gabapentin 600 mg/day and 900 mg/day group at any point of time (P>0.05). Conclusion: The results of this study show that gabapentin is effective in acute herpetic neuralgia in different doses with 600 mg/day being the more appropriate dose in terms of safety and efficacy.