Abecarnil, a new beta-carboline, in the treatment of anxiety disorders

Abecarnil, a novel anxiolytic beta-carboline, was investigated in five four-week double-blind, European multicentre studies. Overall 451 patients with generalised anxiety disorder were randomised to abecarnil, 461 to placebo and 464 to active controls.

Data includes inferential statistics based on individual studies and descriptive analysis of 323 patients in open-label abecarnil long-term continuation up to 52 weeks.

Abecarnil was safe, the most frequent adverse event being drowsiness. Onset of effect was at week 1. At week 4 the Hamilton Anxiety Scale score had improved by 12-13 points on average. Due to notably large and variable placebo effects abecarnil was not consistently superior to placebo. No rebound or withdrawal symptoms were observed after fast-tapered discontinuation. Safety, extent of efficacy and incidence of rebound or withdrawal did not change during long-term treatment.

Abecarnil is safe and effective. Further research into its therapeutic potential seems warranted.