Gabapentin, brand name - Neurontin, is a medication used to treat epilepsy, neuropathic pain, hot flashes, and restless leg syndrome. This study shows that dosage concentration greatly effects the treatment of postherpetic neuralgia according to the interpretation of the statistical results. 

Postherpetic neuralgia (PHN) is a sequela of herpes zoster that adversely affects quality of life seriously. The risk factors for PHN are well known but the effective interventions that reduce the incidence of PHN are less studied. The objective of this study is to evaluate the efficacy of treatment with gabapentin in patients with acute herpes zoster for preventing PHN. 

We performed a prospective randomized controlled study of 120 participants diagnosed with acute herpes zoster, aged 50 and over and complaining moderate to severe pain. All patients were treated with valacyclovir and acetaminophen. Half of the participants were assigned to the gabapentin group and received gabapentin 300 mg three times a day additionally. The intensity of pain at every visit and the incidence of PHN in both groups were measured. Total 52 and 49 patients in the gabapentin group and the control group, respectively, had completed 12 weeks of follow-up period. 

Although the incidence of PHN was higher in the control group, the difference was not statistically significant (6.1% vs. 3.8%, p = 0.67). 

Our results indicate that the use of low-dose gabapentin in acute herpes zoster seems not effective in the prevention of PHN.