Although viral diseases can’t be cured, doctors can prescribe oral antiviral medications, such as Zovirax (acyclovir), Famvir (famciclovir) and Valtrex (valacyclovir), that help control the infection by hindering reproduction of the virus in the nerve cells. "Antiviral therapy may shorten the course of an episode of shingles," says Cvetkovich. "However, therapy must be started as early as possible after symptoms develop–within 48 hours–in order to have an effect."

To relieve pain, the doctor may recommend over-the-counter analgesics (pain-relieving drugs), such as ibuprofen and naproxen, or prescription drugs, such as indomethacin, all members of a class of medications known as nonsteroidal anti-inflammatory drugs. Acetaminophen is also commonly used to relieve the pain. If pain is severe, doctors may add stronger analgesics, such as codeine or oxycodone.

Doctors use other methods to alleviate pain with varying degrees of success. "One of the relatively new medications that I’m enthusiastic about is the Lidoderm patch," says Veronica Mitchell, M.D., director of the pain management center and inpatient pain service at Georgetown University Hospital, Washington, D.C. "It’s the transdermal form of lidocaine and it’s been studied in the PHN population with very good results," adds Mitchell. "We prescribed the Lidoderm patch for a patient who had intolerable side effects with oral medications–and no relief–and she’s had about a 50 percent-plus improvement in pain relief. It’s one of my first-line therapies." The medication contained in this soft, pliable patch penetrates the skin, reaching the damaged nerves just under the skin without being absorbed significantly into the bloodstream. This means that the patch can be used for long periods of time without serious side effects.

Yet another method used to treat PHN is transcutaneous electrical nerve stimulation, or TENS. A device that generates low-level pulses of electrical current is applied to the skin’s surface, causing tingling sensations and offering some people pain relief. One theory as to how TENS works is that the electrical current stimulates production of endorphins, the body’s natural painkillers.

TENS is not for everyone. "TENS didn’t help at all," says Einar Raysor of Rockville, Md. "I found there was a problem in fine-tuning the administration of the electrical current. Low doses of the electrical current didn’t do anything for me. When the technician increased the current, it gave me a painful response. After this happened a couple of times, we dropped the treatment."

As a last resort, invasive procedures called nerve blocks may be used to provide temporary relief. These procedures usually entail the injection of a local anesthetic into the area of the affected nerves. "We have controversial results in the terms of the efficacy of nerve blocks," says Mitchell. "I do consider nerve blocks in treating PHN and I would perform them because there’s some evidence that they work, but the real efficacy is to catch and treat the patient in the acute shingles phase. As PHN presents mostly in the elderly, and the older patient often is unable to tolerate some of the medications we use, I find nerve blocks useful in these cases."

Injection directly into the spine is another option for relief of pain that is not easily treated. A Japanese clinical study published in the New England Journal of Medicine found that an injection of the steroid methylprednisone combined with the anesthetic lidocaine reduced pain by more than 70 percent in one patient group compared with groups that received lidocaine alone or an inactive substance.
References :
http://www.fda.gov/fdac/features/2001/301_pox.html