The shingles is a reactivation of the chicken pox (also known as varicella-zoster) which occurs in the distribution of usually one, but sometimes more than one, peripheral nerve. It begins with a red rash that eventually causes vesicular (fluid filled) lesions and it is very painful. When this occurs, in general, the patient should be treated with a medications that works against the virus itself such as acyclovir (Zovirax®), famciclovir (Famvir®), or valacyclovir (Valtrex®). The duration of the vesicles is usually one to two weeks. The shingles usually reactivates when the body is being affected by another stress such as an illness, surgery, or cancer. Usually the pain subsides when the skin lesions heal.

Unfortunately, for 10-20% of all patients who get the shingles, the pain does not subside. When the pain persists long (one month by some authors, 3 months by others) after the vesicles are healed, this is called a post-herpetic neuralgia. The chance of having a post-herpetic neuralgia increases with increasing age and is in about 60% of those patients who are over 60. The natural history of this disease is to improve and only a small percentage of patients with this disease have persisting pain greater than one year.

The only FDA approved treatments for this condition is Neurontin®, an anti-epileptic drug (AED) and Lidoderm®, a topical lidocaine preparation. Lidoderm® is applied for sixteen hours to the affected area and removed for eight hours. Unfortunately, sometimes the location or size of the area make it impossible or impractical to use the Lidoderm®. In addition, some patients do not get sufficiently long relief of pain during the twelve hours the patch has to be removed each day.

Neurontin® has been demonstrated in two placebo controlled trials to be effective in decreasing the pain of post-herpetic neuralgia. The medication is extremely safe and well tolerated. When Neurontin® is not successful, then other AEDs should be tried as the response to one medication does not predict a response to the others. Most commonly Tegretol® has been used but now many of the newer AEDs are gaining favor. Commonly used AEDs include Trileptal and Keppra. Less frequently used are Topamax, Zonegran, and Lamictal.

Another cream commonly tried by patients is capsaicin cream. Capsaicin cream can also be used but it typically causes more pain before the pain subsides and it must be reapplied religiously three times daily.

Additional medications used for post-herpetic neuralgia include the tricyclic antidepressants such as Elavil® (amitriptyline) or Pamelor (nortriptyline). These medications, however, sometimes cause too many side effects including weight gain, constipation, and sleepiness. In addition, these medications are usually not recommended for patients over the age of 65 due to an increased risk of falls.

Dr. Loftus is currently participating in two trials to treat post-herpetic neuralgia patients. One trial is only for those who are 3-9 months from the onset of their rash. More information is available here. A second trial is for those who are more than 3 months from the onset of their rash. Information about that trial is located here.