From the Guidelines
Topical agents for post-herpetic neuralgia, such as lidocaine 5% patches, are recommended as a first-line treatment due to their localized pain relief and minimal systemic absorption. The use of topical agents for post-herpetic neuralgia is supported by several studies, including a 2017 clinical practice guideline for the management of chronic pain in patients living with HIV, which identified lidocaine patches as an effective treatment for post-herpetic neuralgia with a number needed to treat (NNT) of 2 1. Other topical agents, such as capsaicin 0.075%, have also been found to be effective in relieving neuropathic pain, although the evidence is limited by low numbers of patient episodes 1.
Some key points to consider when using topical agents for post-herpetic neuralgia include:
- Lidocaine 5% patches can be applied to the painful area for up to 12 hours daily, providing localized pain relief without significant systemic absorption 1
- Capsaicin 0.075% can be applied sparingly three to four times per day to the affected area, although it may cause worsening of neuropathic symptoms for the first few weeks of application 1
- Compounded creams containing combinations of medications like amitriptyline, ketamine, and lidocaine may also be effective, although the evidence is limited and they may cause local skin reactions like erythema or burning sensations 1
Overall, the use of topical agents for post-herpetic neuralgia is a valuable treatment option, particularly for elderly patients or those who cannot tolerate systemic medications due to their minimal systemic side effects. The most effective topical agent for post-herpetic neuralgia is lidocaine 5% patches, which have been shown to provide localized pain relief without significant systemic absorption 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Topical Agents for Post-Herpetoc Neuralgia
Other topical agents for post-herpetoc neuralgia include:
- Capsaicin, which has been shown to be effective in relieving hypersensitivity and hyperalgesia in patients with PHN 2
- Lidocaine, which is available in various formulations, including patches and plasters, and has been shown to be effective in providing pain relief and reducing allodynia 3, 2, 4
- Opioid analgesic treatment, which may be used as an alternative therapy for PHN 5
Comparison of Topical Agents
Studies have compared the efficacy and safety of different topical agents for PHN, including:
- A systematic review that compared 5% lidocaine-medicated plaster with other relevant interventions and placebo, and found that 5% lidocaine-medicated plaster was effective in providing pain relief and reducing allodynia, with fewer adverse events than systemic agents 4
- A study that found that topical capsaicin was effective in relieving hypersensitivity and hyperalgesia in patients with PHN, but had a lower efficacy than 5% lidocaine-mediated plaster 4
Safety and Efficacy
The safety and efficacy of topical agents for PHN have been evaluated in several studies, including: