Shingles (herpes zoster) is caused by the varicella-zoster virus, the same virus that causes chickenpox, according to background information in the article. The virus lays dormant in the nervous system for decades after infection with chickenpox. When it becomes reactivated, the virus causes a rash and nerve pain (postherpetic neuralgia). Postherpetic neuralgia can that lasts for months or years and affects as many as one million people in the United States.
Dianna Quan, M.D., and colleagues at the University of Colorado and Health Sciences Center, Denver, administered antiviral therapy to 15 patients (12 men and three women) with moderate to severe nerve pain following shingles. Participants received 10 milligrams of the medication acyclovir intravenously every eight hours for 14 days and then took three 1,000-milligram pills of the medication valacyclovir per day for one month. The patients were asked to rate their pain on a scale of zero to 10 at the beginning of the study, then again after finishing each therapy and one month after finishing valacyclovir.
One month after therapy, eight (53 percent) patients reported that their pain had reduced significantly (by two or more points). This was similar to the percentage of patients who reported such an improvement after day 15 (seven) and after day 45 (eight). Most patients tolerated the treatment well, although five dropped out of the study early, three of them because of complications related to the therapy.
"Although our study was small and without placebo control, the findings suggests a promising effect of antiviral treatment on postherpetic neuralgia," the authors conclude. "Treatment of postherpetic neuralgia with IV acyclovir will be expensive. However, elimination or reduction of pain coupled with reduced burden of disease and use of health care resources would offset treatment costs."
(Arch Neurol. 2006; 63: (doi: 10.1001/archneur.63.7.noc60049). Available pre-embargo to the media at www.jamamedia.org)
Editor's Note: This study was supported in part by grants from the National Institutes of Health and a grant from the Avenir Foundation.