Capsaicin 8% topical patch (Qutenza)--a review of the evidence.

Qutenza is a high-potency capsaicin (8%) topical patch, labeled for treating pain associated with postherpetic neuralgia (PHN). Qutenza decreases pain sensation by reducing transient receptor potential vanilloid 1 (TRPV1) expression and decreasing the density of epidermal nerve fibers in the application area. Systemic absorption from Qutenza is low. Qutenza has not been directly compared to any other medications for the treating PHN. Two pivotal clinical trials compared Qutenza to a control patch (0.04% capsaicin) in PHN. The primary endpoint of both trials was the reduction in numeric pain rating scale (NPRS) score. Qutenza reduced pain from baseline to weeks 2 to 8 (29.6% and 32% reductions) compared to control (19.9% and 24.4% reductions; P ≤ .01). The improvement in NPRS scores persisted, with score reductions greater with Qutenza (29.9% and 32.3% reductions) compared to control (20.4% and 25% reductions; P ≤ .03) for the period 2 to 12 weeks. Safety and efficacy of capsaicin 8% has been demonstrated in open-label trials for up to 48 weeks. The most common adverse drug reactions occurring with capsaicin 8% are application site erythema (63%) and application site pain (42%). Some patients experienced transient increases in blood pressure during Qutenza application. Qutenza must be administered by a physician or under the close supervision of a physician. Prior to application, pretreat the affected area with a topical anesthetic to reduce application site pain. Some patients may require systemic analgesics during and after treatment for treatment-associated pain. Applications of Qutenza can be repeated no sooner than once every 3 months, as needed.