Journal of pharmaceutical sciences
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Topical lidocaine has been recently marketed as a new treatment for post-herpetic neuralgia. The aim of our study was to characterize the absorption profile of and systemic exposure to lidocaine from patch and gel formulations in normal volunteers, patients with post-herpetic neuralgia, and patients with acute herpes zoster. ⋯ Systemic exposure to lidocaine and monoethylglycinexylidide (MEGX), the primary active metabolite of lidocaine, after application of lidocaine gel or patches was minimal in normal volunteers, patients with post-herpetic neuralgia, and patients with acute herpes zoster. Considering the benefit versus risk of topical lidocaine, systemic absorption and toxicity of lidocaine seems not to be a significant risk.