Nonbenzodiazepine

Nonbenzodiazepines (/ˌnɒnˌbɛnzoʊdaɪˈæzɪpiːn, -ˈeɪ-/), sometimes referred to colloquially as Z-drugs (as many of their names begin with the letter "z"), are a class of psychoactive, depressant, sedative, hypnotic, anxiolytic drugs that are benzodiazepine-like in uses, such as for treating insomnia and anxiety.

Nonbenzodiazepine pharmacodynamics are similar in mechanism of action to benzodiazepine drugs, acting as GABA_A receptor positive allosteric modulators of the benzodiazepine site, and therefore exhibit similar benefits, side effects, and risks. However, nonbenzodiazepines have dissimilar or entirely different chemical structures, so are unrelated to benzodiazepines on a molecular level.

Nonbenzodiazepines have demonstrated efficacy in treating sleep disorders. There is some limited evidence that suggests that tolerance to nonbenzodiazepines is slower to develop than with benzodiazepines. However, data is limited so no conclusions can be drawn. Data is also limited into the long-term effects of nonbenzodiazepines. Further research into the safety of nonbenzodiazepines and long-term effectiveness of nonbenzodiazepines has been recommended in a review of the literature. Some differences exist between the Z-drugs, for example tolerance and rebound effects may not occur with zaleplon.

Currently, the major chemical classes of nonbenzodiazepines are:

Imidazopyridines

Pyrazolopyrimidines

The nonbenzodiazepines are positive allosteric modulators of the GABA_A receptor. Like the benzodiazepines, they exert their effects by binding to and activating the benzodiazepine site of the receptor complex.

Some nonbenzodiazepines can be subtype-selective, possibly providing anxiolytic effects with little to no hypnotic or amnesic effects or providing hypnotic effects with little or no anxiolytic effect.