Topical Treatment of Peripheral Neuropathic Pain: Applying the Evidence

Abstract Context Patients with peripheral neuropathic pain (NP) may only achieve partial pain relief with currently recommended first-line oral treatments, which are also associated with systemic adverse events. Topical treatments are currently considered second- or third-line options, but a recent pharmacological treatment algorithm has called for broader first-line use of these agents. This has highlighted a need to communicate the benefits associated with topical agents, in particular around the efficacy, targeted local action and limited systemic availability resulting in minimal systemic adverse events and drug–drug interactions. Objectives This review aims to evaluate the evidence base for topical therapies currently used to treat peripheral NP, discuss the evidence comparing these treatments head-to-head with oral standard of care, and evaluate how they fit into treatment regimens in the ‘real world’. Methods This is a narrative review. Results Two topical treatments are currently licensed: lidocaine 5% medicated plaster (post-herpetic neuralgia [PHN]) and the capsaicin 8% patch (peripheral NP). When compared head-to-head with the oral standard of care (pregabalin), the lidocaine 5% medicated plaster provided similar relief of pain associated with PHN but did not meet the primary predefined criteria for non-inferiority. The capsaicin 8% patch, however, demonstrated non-inferior efficacy when compared head-to-head with pregabalin across a wide range of peripheral NP etiologies. Importantly, both treatments demonstrated effective pain relief without the systemic adverse events associated with oral therapies. Conclusions First-line use of topical agents may be of particular benefit in patients where the safety and tolerability of oral therapy is a concern.