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

BACKGROUND: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: Abecarnil is safe and effective. Further research into its therapeutic potential seems warranted.