NEW YORK (Reuters Health) - A study shows that the powerful prescription painkiller oxycodone is an effective treatment for the sometimes excruciating pain of shingles.

Shingles is caused by reactivation of varicella zoster virus, which causes chickenpox and then lays dormant in nerve fibers. When it's reactivated, often by trauma or stress, the virus can produce a very painful skin eruption.

"Oftentimes patients are told that the rash will heal in two or three weeks anyway, and the pain will go away, so they're not given something for the pain unless it's excruciating," Dr. Robert Dworkin noted in a statement. "But moderate pain can stop people from working, or enjoying their hobbies, and it can also make some people depressed or anxious. So there's good reason to treat all pain from the infection."

In a study of 87 patients with significant shingles-related pain, Dworkin, from the University of Rochester School of Medicine and Dentistry, New York, and colleagues assessed the pain-relieving punch of oxycodone and gabapentin, which both effectively treat pain associated with nerve damage, compared with placebo.

According to a report in the journal Pain, patients taking oxycodone were more than twice as likely to experience a meaningful reduction in their pain - at least a 30 percent decrease - compared to their counterparts taking a placebo. Though the medication was effective, nearly one-third of the participants on oxycodone withdrew from the study, mainly because of problems with constipation.

Gabapentin was not significantly better than placebo for pain relief, although there was evidence of modest benefit during the first week of treatment. The investigators say it's possible a higher dose would be necessary to adequately treat shingles pain. However, the medication must be increased over the course of 3 weeks or more, they note, which is often too long to have much of an effect on acute shingles pain that can go away in a few weeks..

"By demonstrating that controlled-release oxycodone is safe, generally adequately tolerated, and efficacious in relieving acute pain in patients with herpes zoster (shingles), the results of this clinical trial provide a foundation for evidence-based treatment for herpes zoster pain," the investigators conclude.

SOURCE: Pain, April 2009.

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