The US FDA has approved Eli Lilly's antidepressant Cymbalta (duloxetine HCl), judging it safe and effective for the management of diabetic peripheral neuropathic pain, a symptom of nerve damage, the company announced here.

Cymbalta, a balanced and potent serotonin and norepinephrine reuptake inhibitor, is the first and only FDA-approved treatment for pain caused by diabetic peripheral neuropathy. This approval came after a six-month priority review, the company release says.

The recognition for Cymbalta in the treatment of pain caused by diabetic peripheral neuropathy at doses of 60 and 120 mg per day came in two randomized, 12-week, double-blind, placebo-controlled, fixed-dose studies in non-depressed adults who had the disorder for at least 6 months. However, doses of 120 mg per day, although safe and effective, were not as well tolerated as 60 mg per day. On average, patients in the studies were 60 years old, suffered from diabetes for 11 years and from related diabetic neuropathy for four years, and at the beginning of the studies, rated their pain as moderate to moderately severe, the release added.

In both studies, Cymbalta significantly reduced 24-hour average pain, compared with placebo. Improvements were noted as early as the first week of treatment and continued for the duration of the studies. In addition, Cymbalta showed rapid onset of action and sustained effect in reducing pain caused by diabetic neuropathy at both 60 mg per day and 120 mg per day, and was effective in relieving pain at night.

"Until now, we didn't have a simple and effective therapy for patients living with diabetic neuropathic pain. Instead, we were left with medications that often required multiple dose adjustments, or for patients to take several pills throughout the day. This is difficult for many of these patients, as they already take a host of medications for their diabetes and other conditions, which can put them at increased risk for drug interactions and dose-limiting side effects," said Timothy Smith, medical director, Mercy Health Research, St. Louis, and a Cymbalta investigator. "With Cymbalta, we finally have a therapy proven to provide real relief for many of these patients, without the complicated dosing schedule," he added.

Although Cymbalta does not change the underlying nerve damage caused by diabetic peripheral neuropathy, it does help relieve the stabbing, burning and shooting pain often associated with the disorder. Scientists believe it does this by increasing levels of serotonin and norepinephrine, two neurotransmitters, or chemical messengers, believed to be important in regulating a person's emotions as well as sensitivity to pain. Increasing these levels in a balanced way is thought to improve the body's natural ability to regulate pain, the release says.

"We know that Cymbalta, as an antidepressant, is effective at treating both the emotional and painful physical symptoms of depression," Stephen Stahl, chairman of the Neuroscience Education Institute and adjunct professor of psychiatry at the University of California at San Diego School of Medicine said adding, "Seeing significant benefit in diabetic neuropathic pain, among patients who did not have depression, helps confirm that this drug has a positive impact on pain that is separate from improvement in mood."

This is the second time in a month that the FDA has judged Cymbalta a safe and effective therapy for a major medical disorder. On Aug. 3, the agency approved Cymbalta as a treatment for major depression in adults.

According to the National Institute of Diabetes & Digestive & Kidney Diseases, approximately half of those with diabetes have some form of nerve damage, or neuropathy, but not all will develop symptoms. While nerve problems can occur at any time, the highest rates are among those who have had diabetes for at least 25 years.