Tolerance to a new class of non-benzodiazepine anxiolytics.

The development of tolerance to the pharmacodynamic effects of azopirone (buspirone) and imidazopyridines (alpidem and zolpidem) was investigated. It was found that tolerance to the anxiolytic effect of buspirone develops only after 42 days of administration (twice daily). Of the imidazopyridines alpidem showed an anxiolytic activity, while after zolpidem only a sedative activity was seen. No tolerance to the anxiolytic and sedative activity of the evaluated imidazopyridines could be detected. On the other hand tolerance appeared in the conditioned avoidance response test (evaluating learning and memory).