Wyeth has been granted approval in the USA to expand the labeling for its antidepressant drug Effexor XR (venlafaxine) to include the treatment of adults with panic disorder.

Panic disorder affects 2.4 million American adults annually, according to Wyeth, and the condition is characterized by recurrent, unexpected panic attacks.

Effexor XR is the first new treatment to be approved for panic disorder since 2002, the company said in a statement. It is already approved to treat depression, generalized anxiety disorder and social anxiety disorder in adults in the USA, and remains one of Wyeth’s top-selling drugs.

Revenues for Effexor XR and its immediate-release parent Effexor came in at $861 million dollars in the third quarter of 2005, a 4% decline owing to generic competition affecting the whole antidepressant sector, so the new indication provides an extra boost for the franchise as a whole.

Wyeth has been able to fend off generic competition to Effexor XR in the US market, which accounted for $589 million of third quarter sales, by striking a deal with generic drugmaker Teva Pharmaceutical Industries, which was angling to launch a rival version of the drug.