Subcutaneous Injection of Botulinum Toxin A Is Beneficial in Postherpetic Neuralgia

Objective. To assess the benefits of subcutaneous injection of botulinum toxin A (BTX‐A) for the treatment of postherpetic neuralgia (PHN). Design. We investigated the therapeutic benefits of BTX‐A in subjects with PHN in a randomized, double‐blind, placebo‐controlled study. Sixty subjects with PHN were randomly and evenly distributed into BTX‐A, lidocaine, and placebo groups. Measures. After randomization, one of the following solutions was injected subcutaneously in the affected dermatome: 5 u/mL BTX‐A, 0.5% lidocaine, or 0.9% saline (placebo). Visual analog scale (VAS) pain and sleeping time (hours) were evaluated at the time of pretreatment, day 1, day 7, and 3 months posttreatment. Opioid usage was calculated at day 7 and 3 months posttreatment. Results. Compared with pretreatment, VAS pain scores decreased at day 7 and 3 months posttreatment in all three groups (P