Neuropathic pain presents a difficult challenge. When the peripheral or central nervous system isn't functioning correctly, it can lead to pain that continues for months or years.
NEUROPATHIC PAIN presents a difficult challenge for both patients and clinicians. It is unlike pain resulting from a muscle or ligament injury-as those injuries heal, pain diminishes.
Neuropathic pain is quite different. When the peripheral or central nervous system isn't functioning correctly, this can lead to pain that continues for months or years. In addition to pain, malfunctioning nerves may produce a range of unusual sensations, including numbness, tingling, burning, extreme sensitivity to touch, and muscle weakness.
Many different illnesses can produce neuropathic pain, including kidney disorders, hormonal imbalances, vitamin deficiencies, tumors and autoimmune disorders. In the United States, diabetes is the leading cause of peripheral neuropathies, and 60% to 70% of people with diabetes have mild to severe forms of nerve damage. Infections can also lead to neuropathies, including the herpes virus, Epstein-Barr virus, AIDS and Lyme disease. In some cases, no specific cause for neuropathic pain can be found. These conditions are difficult to treat.
A specific medication may be of enormous benefit for one patient, and not be effective at all for another patient.
"You run the gamut," Dr. Lewis says. "It takes a great deal of interaction between the health professional and the patient to come up with an appropriate dose they can tolerate that diminishes their pain. Sometimes it takes months, even years, to come up with the right regimen."
Antiepileptics and antidepressants are among the most effective medications for neuropathic pain. Antiepileptics were originally used to treat seizures, but some have been shown to be effective for certain forms of nerve pain. They include:
In addition, a number of antidepressants are effective in treating neuropathic pain, Dr. Lewis says.
"Tricyclic antidepressants such as Elavil (amitriptyline) or Pamelor (nortriptyline) in particular are quite helpful in treating pain, and the effect on pain seems to be independent of its antidepressant qualities," he says.
He notes that antidepressants have a number of different effects. They help people sleep through the night, which is important because lack of sleep intensifies the sensation of pain.
"In addition, some antidepressants have specific effects on pain mechanisms, and then if someone is depressed, it will help the depression," he says.
When it comes to more recent antidepressants, called SSRIs, the ones that are most effective against neuropathic pain are the serotonin-norepinephrine reuptake inhibitors (SNRIs), Dr. Lewis says.
"Cymbalta (duloxetine) in particular has been shown to be effective not only in diabetic neuropathy but also in fibromyalgia, for instance," he says. "But when you look at the full list of SSRIs, only a few of them have been shown to be effective in pain."