Liposomal topical capsaicin in post-herpetic neuralgia: a safety pilot study.

UNLABELLED: Topical treatments have gained popularity for general use as an adjunct to systemic drugs in neuropathic pain, but their use produces variable clinical results and local adverse events. OBJECTIVE: To evaluate the safety and analgesic effect of a formulation of liposomal capsaicin (LC) (0.025%) in patients with post herpetic neuralgia (PHN). METHOD: Patients who remained symptomatic after first-and second-line treatment were randomized to receive LC for six weeks in a placebo-controlled, crossover design study. Clinical assessment was performed at baseline, in the second, fourth and sixth week of treatment. RESULTS: Thirteen patients completed both treatment periods. Visual Analog Scale (VAS) was significantly decreased after the end of the study (p = 0.008), however the effect of treatment was not significant (p = 0.076). There was no difference on global impression of change and other pain characteristics. LC was safe and well tolerated. However, at the concentration used, its analgesic effects were marginal and not significant.