In a clinical trial of a new type of drug to relieve severe, chronic pain caused by nerve damage, the anti-convulsant medicine gabapentin has provided significant relief from the aching, burning, tearing pain that some shingles patients suffer for years after other symptoms subside.
Shingles, caused by the virus Herpes zoster, results from the reactivation of the chickenpox virus and attacks more than a million people in the United States each year. While the shingles rash and pain eventually subside in most people, about 10 to 15 percent experience continued severe pain known as postherpetic neuralgia, or PHN, which can last years, and often the rest of an older patient's life.
The shingles clinical trial was reported in the December 2 issue of the Journal of the American Medical Association (JAMA) by University of California San Francisco neurologist Michael Rowbotham, MD, and colleagues at the Rehabilitation Institute of Chicago, Oregon Health Sciences University, and Parke-Davis Pharmaceutical Research, which funded the study.
Soon after gabapentin came into use in 1995 to treat epilepsy, physicians noted its pain-relieving powers. The shingles study reported in the Dec. 2 issue of JAMA is one of two multi-center studies to test the drug's ability to control severe pain associated with nerve damage. A report on its ability to relieve pain from diabetic neuropathy is also published in the Dec. 2 JAMA issue. An editorial on the promising findings, written by Mayo Clinic neurologist Phillip Low, appears in the same issue.
Tricyclic antidepressants are the principal drug used to treat PHN
pain, but they don't work for more than half of those who try them, and
many cannot tolerate their side effects, which include decreased blood pressure,
constipation and forgetfulness, Rowbotham said. Most PHN sufferers are elderly,
making these side effects particularly unacceptable. In contrast, gabapentin
appears to be at least as
Contact: Wallace Ravven
University of California - San Francisco