Challenges with current treatment of neuropathic pain

Neuropathic pain refers to pain that originates from a lesion or dysfunction of the peripheral or central nervous system. Common examples are painful diabetic neuropathy and post-herpetic neuralgia. Despite recent advances in the identification of pain-generating mechanisms and the introduction of evidence-based treatment guidelines, patients with neuropathic pain are challenging to manage. The currently available systemic therapies provide about half of affected patients with meaningful pain relief and are further limited by unwanted adverse effects, such as drowsiness and dizziness, and the need for multiple daily dosing. The traditional topical agents available for the treatment of neuropathic pain - lidocaine patch (5% w/w) and low-concentration capsaicin cream (0.075% w/w) - are generally free of systemic adverse effects but they have only modest efficacy, require cumbersome daily administration, and in the case of capsaicin cream can lead to discomfort and contamination of sensitive body areas, all of which may result in poor compliance. As patients are left with a difficult compromise between pain relief on the one hand and adverse effects and daily treatment regimens on the other, a clear unmet need remains in the management of neuropathic pain. A high-concentration capsaicin (8% w/w) patch that provides rapid and prolonged pain relief from a single application is a promising alternative treatment option for patients with peripheral neuropathic pain. Further elucidation of the specific pathophysiologic mechanisms which contribute to neuropathic pain and their translation into signs and symptoms should ultimately enable the design of optimal treatments for individual patients with neuropathic pain.