Source: Graefes Arch Clin Exp Ophthalmol  |  Posted 6 years ago

By Bonnie Darves

SEATTLE, WA -- March 21, 2005 -- Extended-release venlafaxine may provide better short-term treatment of panic disorder than paroxetine, if given in 225-mg doses, but both drugs are effective in reduction of acute symptoms, according to new research presented here March 19[^]th[] at the Anxiety Disorders Association of America 25[^]th[] Annual Conference.

"Both [drugs] were effective, but we found some suggestion of a reuptake dose response advantage with the higher venlafaxine dose versus the paroxetine," said the study's chief author Mark Pollack, MD, director, Anxiety Disorders Program, Massachusetts General Hospital, Boston, Massachusetts, United States.

The 12-week, randomized, double-blind, controlled study enrolled 626 patients who were randomized to venlafaxine at one of two different doses (75 and 225 mg), 40 mg paroxetine or placebo. The study's primary objective was to compare the two venlafaxine doses to placebo in patients with panic disorder of at least 3 years' duration. The paroxetine efficacy comparison to venlafaxine was a secondary objective.

Nearly 90% of patients on high-dose venlafaxine were deemed to be responders, compared to approximately 83% of those on either low-dose venlafaxine or paroxetine.

At endpoint, 70% of high-dose venlafaxine patients were free of full-symptom panic attacks, versus 58% of patients on paroxetine. "Roughly half of all patients in active treatment arms were remitters," Dr. Pollack said.

Discontinuation rates were comparable among the three treatment groups, but significantly higher in the placebo group (43 for those on placebo versus 29 on the higher dose venlafaxine and 35 on paroxetine).

A previous randomized, double-blind, controlled trial of the two medications had found comparable efficacy among venlafaxine in 75 mg and 150 mg doses, and paroxetine. Venlafaxine, a selective norepinephrine reuptake inhibitor (SNRI), has been found effective in the treatment of depression and anxiety disorders.

In this study, patients were predominantly female and had a mean age of approximately 36 years. Baseline scores on the Hamilton anxiety rating scale were comparable among the four groups, at a mean of 9.7, Dr. Pollack said.

[Presentation title: Short-Term Treatment of Panic Disorder: Comparison of Venlafaxine XR vs. Paroxetine or Placebo. Poster 159]