Is tofisopam an atypical anxiolytic?

This review describes the behavioural and biochemical profile of tofisopam, a 3,4-benzodiazepine that differs considerably in its effects and mechanisms of action from classical 1,4-benzodiazepines. In man tofisopam appears to possess anxiolytic activity without appreciable sedative and muscle relaxant side effects; in animals, however, tofisopam totally lacks anxiolytic and anticonvulsant properties in tests sensitive to the effects of 1,4-benzodiazepines. Tofisopam also has mixed dopamine agonist and antagonist-like properties in several in vivo and in vitro tests in animals. The possible relevance of the latter effects to the unusual behavioural profile of tofisopam are discussed, and its effects compared with those of buspirone, a novel anxiolytic that has similar activity at benzodiazepine and dopamine systems. It is proposed that these two drugs may represent a novel class of compounds that reduce anxiety by increasing the ability of patients to cope with daily tasks, rather than classical anxiolytics, that reduce anxiety by tranquilization.