Studies with alpidem in normal volunteers and anxious patients

Alpidem, an imidazo-pyridine compound, has been evaluated as an anxiolytic in comparison with placebo and lorazepam. In the first of our normal volunteer studies, we compared single doses of alpidem, 25, 50 and 100 mg with lorazepam 2 mg and placebo on a range of cognitive, psychomotor and EEG variables. Lorazepam and the highest (100 mg) dose of alpidem impaired performance on a range of psychomotor tasks, the effects of the benzodiazepine being more severe and more prolonged. No impairment of performance was observed with the 25 and 50 mg doses. In the second study, the focus was on memory functions. Lorazepam, 2 mg, caused anterograde amnesia which was most apparent 1 h post-drug but persisted until 4 h: sedation was marked. By contrast, single doses (25, 50 mg) of alpidem had little effect on either memory or alertness. The third study compared the effects of alpidem (25, 50 mg) and lorazepam (1 mg) with placebo, each given twice-daily for 8 days to normal volunteers. On the final day, a test dose of ethanol was given. Lorazepam impaired many tests of cognitive and psychomotor function, and this impairment was enhanced by ethanol. By contrast, alpidem produced less impairment with less interaction with alcohol. In a fourth, clinical, study, 24 patients with a DSM III primary diagnosis of generalised anxiety disorder were treated, under double blind conditions, with doses adjusted according to clinical need of either alpidem 25-150 mg daily or lorazepam 1-6 mg daily.(ABSTRACT TRUNCATED AT 250 WORDS)