Memantine as a Potential Therapy in Subacute Herpetic Neuralgia: A Randomized Clinical Trial

Varicella-Zoster virus (VZV) is the causative agent of herpes zoster, or "shingles." Most cases of acute herpes zoster are self-limiting, although the pain can cause significant suffering, and experience postherpetic neuralgia (PHN), particularly in older adults. Early treatment of herpetic neuralgia in the subacute phase may prevent PHN progression. This study aimed to evaluate the efficacy of memantine in the treatment of subacute neuropathic herpes zoster. 

This randomized clinical trial was performed on sixteen patients aged 18-75 years with subacute herpetic neuralgia. Patients were randomly assigned to the intervention or control group according to the inclusion and exclusion criteria (8 in each group). The duration of the study was eight weeks. Patients in the memantine group received Gabapentin 300 mg per day and memantine 5 mg twice a day. Then, after one week, the memantine dose was tapered up to 10 mg twice a day. In the control group, patients received only Gabapentin from the first week to the end of the study. DN4 questionnaire is used to measure the severity of nerve pain. The patients of both control and intervention groups completed the questionnaire before starting the treatment and it was done again after the end of the treatment period (8 weeks).

The results showed improvement in pain in patients who received Memantine along with Gabapentin in comparison with Gabapentin alone (P =0.001). Moreover, the DN4 questionnaire score evaluation indicated a significant difference only for the intervention group's Q1 variable in within-group analysis (P =0.031).

Co-administration of memantine with Gabapentin reduced the severity of subacute neuropathic herpes. In addition, memantine is expected to be a viable option for treating and relieving subacute and chronic nerve pain in patients.