Estimates are that 16 million people in the United States have diabetes. The common infection shingles, caused by the virus herpes zoster, strikes 1 million people annually and also causes chronic pain in about 15 percent of patients. Known as post-herpetic neuropathy, this condition is also difficult to treat. In shingles, the nerves are damaged by the herpes zoster virus.
Antidepressants are the standard treatment for both types of neuropathies.
But those drugs, which can cause irregular heartbeat, sedation, confusion, precipitous declines in blood pressure and other complications, control pain in only about half of patients. Several groups of researchers are seeking better ways to control these types of chronic nerve pain. Neither researchers nor the patients knew who received gabapentin until after the study ended. Participants in the study were also evaluated using an 11-point pain scale. Patients who were already taking either narcotics or antidepressants continued taking those drugs during the study.