Publication Bias Inflates Apparent Efficacy of Alprazolam XR

One of five trials in the FDA review was positive; all three trials in the published literature were positive

By Elana Gotkine HealthDay Reporter

WEDNESDAY, Nov. 22, 2023 (HealthDay News) — Publication bias inflates the apparent efficacy of alprazolam extended-release, according to a study published online Oct. 19 in Psychological Medicine.

Rosa Y. Ahn-Horst, M.D., M.P.H., from Massachusetts General Hospital in Boston, and Erick H. Turner, M.D., from the Veterans Affairs Portland Health Care System in Oregon, examined publication bias with alprazolam by comparing its efficacy for panic disorder using trial results from the published literature and the U.S. Food and Drug Administration. Data were included from all phase 2/3 efficacy trials of alprazolam extended-release (Xanax XR) for the treatment of panic disorder.

The researchers identified five trials in the FDA review, one of which had positive results (20 percent). Of the four trials without positive results, two were published conveying a positive outcome and two were not published. Therefore, according to the three published trials, 100 percent were positive. Using FDA data, alprazolam’s effect size was 0.33 versus 0.47 using published data, representing a 42 percent increase.

“Clinicians are well aware of these safety issues, but there’s been essentially no questioning of their effectiveness,” Turner said in a statement. “Our study throws some cold water on the efficacy of this drug. It shows it may be less effective than people have assumed.”