What is Neuropathic Pain?
Neuropathic pain is a complex, chronic pain state that usually is accompanied by tissue injury. With neuropathic pain, the nerve fibers themselves may be damaged, dysfunctional, or injured. These damaged nerve fibers send incorrect signals to other pain centers. The impact of nerve fiber injury includes a change in nerve function both at the site of injury and areas around the injury.
One example of neuropathic pain is called phantom limb syndrome. This rare condition occurs when an arm or a leg has been removed because of illness or injury, but the brain still gets pain messages from the nerves that originally carried impulses from the missing limb. These nerves now misfire and cause pain.
Managing Neuropathic Pain
The following article discusses the use of topical ketamine 0.5% (5 mg/ml) gel, applied as a thin film two to three times daily over the skin where pain was severe. Topical ketamine reduced pain for patients with postherpetic neuralgia with no systemic side effects.
Neurology. 2003 Apr 22;60(8):1391-2
The following randomized, double-blind, placebo-controlled study assessed the analgesic efficacy of topical administration of 3.3% doxepin hydrochloride, 0.025% capsaicin or a combination applied daily for 4 weeks in 200 adult patients with chronic neuropathic pain, and reported that all three preparations significantly reduced overall pain.