Lidocaine plasters for postherpetic neuralgia?

Each year in the UK, about 1 in 2,500 people experiences neuropathic pain that is still present 3-6 months after acute herpes zoster (shingles). This condition, known as postherpetic neuralgia, is the most common complication of herpes zoster and can be chronic, intractable and distressing. Treatments used in an attempt to reduce postherpetic neuralgia include tricyclic antidepressants (e.g. amitriptyline--an unlicensed indication), antiepileptics (e.g. gabapentin) and opioid analgesics, as well as topical treatments such as capsaicin. However, such treatments may only provide partial pain relief, and tolerability can be a problem, particularly in older patients. Versatis (Grunenthal Ltd), a topical preparation of lidocaine formulated in a plaster, has recently been licensed for treating patients with postherpetic neuralgia. Does it offer useful benefit?