Neurology (57)

New analgesics for neuropathic pain: the lidocaine patch. (North Shore University Hospital, Syosset, NY) Clin J Pain 2000;16:S62–266.
This article reviewed the basis for the development of the lidocaine patch and reviewed the reports of the clinical studies published. Potential uses of the lidocaine patch for other conditions in addition to postherpetic neuralgia (PHN) were also discussed. Conclude that it has been clearly established that the lidocaine patch is a safe and effective treatment for PHN and it is recommended as a first-line treatment based on demonstrated efficacy, quick onset of action, lack of systemic effects, and ease of use with other treatments.
Comment by Enrique Reig, MD.
Intravenous lidocaine is used in pain units for the transient relief of chronic neuropathic pain. If the analgesic result is satisfactory, some physicians start treatment with a lidocaine analogue, oral mexylithene. However, the latter drug is not always well tolerated and its efficacy (in my opinion) is far lower than that of intravenous lidocaine. The recently marketed lidocaine patch is a highly recommended therapeutic alternative if we are considering long-term treatment with lidocaine. Topical agents act locally (skin, soft tissues, peripheral nerves) and do not cause high blood levels (no higher than 0.6 micgr/mL). Topical 5% lidocaine decreases the ectopic discharges from peripheral afferents, reducing nociceptive input to the CNS. There are few side effects and the main indication is postherpetic neuralgia and all those syndromes with peripheral neuropathic pain. The relief that can be expected after using topical 5% lidocaine is not complete, and it can be associated with other types of drugs (anticonvulsants, antidepressants, analgesics, etc.) to obtain a synergistic effect.