Botulinum Toxin Reduction Pain in Postherpetic Neuralgia

The most common complication of herpes zoster is postherpetic neuralgia (PHN), which can cause chronic and debilitating pain. In some patients, pain persists for weeks or even years after regression of the rash and many drugs and methods should be used to treat the pain. As many patients are elder and suffer from chronic diseases, they would be affected by drug complications. Recently, subcutaneous injection of botulinum toxin is used as a new method for controlling pain with little complications. There are a few case studies about effect of botulinum toxin injection to relieve pain. We assessed the effect of subcutaneous injection of botulinum toxin on relieving pain in postherpetic neuralgia. In this intervention study, 15 patients suffer postherpetic neuralgia were enrolled by convincing sampling method. Information as age, sex, dermatome, place and duration of pain, and severity of pain were registered in patients. Then botulinum toxin injected 15 units per 10 cm² subcutaneously. Patients were followed in 2nd day, 2nd week, and 4th week after injection and pain was measured by visual analog score (VAS). Data were analyzed by Repeated Measure ANOVA test using SPSS16 software. Six patients were male and 9 were female. The mean age was 60 ± 4.5 year and duration of pain was 6.5 month. Mean of VAS in 2nd day, 2nd week, and 4th week were 6.4, 7.2, and 7.6 respectively. Patients’ pain in 4th week were decreased compare with before injection but the difference was not statistically significant (P = 0.06). It seemed that subcutaneously injection of botulinum toxin can relieve pain in postherpetic neuralgia. Hence this decrease in duration of the time was observed to be lesser, repetition of injection could be more effective for controlling the pain.