Eli Lilly and Company announced that the US Food and Drug Administration (FDA) has approved the antidepressant Cymbalta (duloxetine HCl) for the treatment of generalized anxiety disorder (GAD), a condition that affects more than 6.5 million American adults in a given year.

Because GAD presents with a variety of symptoms, it can be difficult to diagnose and may have a negative impact on a person's ability to function properly in work, family and social situations.

The safety and efficacy of Cymbalta in the treatment of GAD was established in three randomized, double-blind, placebo-controlled studies in more than 800 non-depressed adults with GAD. In all studies, Cymbalta significantly improved core anxiety symptoms as measured by the Anxiety Scale (HAMA), compared with placebo. In addition, Cymbalta patients reported greater improvement in functional impairment associated with the illness, including improved ability to perform everyday activities at work, home, and in social situations.

"If left untreated, symptoms of generalized anxiety disorder may worsen, potentially impacting many aspects of a person's life, including their job and social relationships," said Susan Kornstein, MD, professor of psychiatry at Virginia Commonwealth University. "With this approval, physicians and patients will be happy to know that there is another medication now available to treat this debilitating condition."

Cymbalta, a member of a class of drugs commonly referred to as serotonin and norepinephrine reuptake inhibitor (SNRI), has been studied in more than 25,000 patients worldwide and is already approved for the treatment of major depressive disorder and management of diabetic peripheral naturopathic pain, both in adults.

"More than 4.5 million adults in the United States have been prescribed Cymbalta for major depressive disorder or diabetic peripheral naturopathic pain," said Mike Detke, MD, PhD, Cymbalta medical director for Eli Lilly and company. "We are excited to offer a new, approved treatment option for generalized anxiety disorder patients and are eager to continue our research with this medication."

In clinical trials, on average, patients treated with Cymbalta for generalized anxiety disorder experienced a 46 per cent improvement in anxiety symptoms compared to 32 per cent for those who took placebo, as measured by the Hamilton Anxiety Scale. In addition, patients in these studies experienced a 46 per cent improvement in function compared to 26 per cent for those who took placebo as measured by the Sheehan Disability Scale.

The most common side effects in these studies included nausea, fatigue, dry mouth, drowsiness, constipation, insomnia, decreased appetite, hyperhidrosis, decreased libido, vomiting, ejaculation delay and erectile dysfunction. In clinical trials, Cymbalta was studied in a dose range of 60-120 mg per day. While a 120mg/day dose was shown to be effective, there is no evidence that doses greater than 60mg/day confer additional benefit. Cymbalta comes in a capsule, and the target daily dose is 60 mg.

Serotonin and norepinephrine in the brain and spinal cord are believed to both mediate core mood symptoms and help regulate the perception of pain. Based on pre-clinical studies, duloxetine is a balanced and potent reuptake inhibitor of serotonin and norepinephrine that is believed to potentiate the activity of these chemicals in the central nervous system (brain and spinal cord).