Buspirone, the prototypical azapirone derivative.

Azapirones, also known as azaspirodecanediones, are a chemical class of psychoactive drugs derived from piperazine that are used as anxiolytics, antidepressants, and antipsychotics. They are commonly used as an augmentation to other antidepressants like the selective serotonin reuptake inhibitors (SSRIs) as well.

Pharmacologically, they are primarily 5-HT_1A receptor partial agonists, and many are also prominent D₂, α₁-adrenergic, α₂-adrenergic, and/or 5-HT_2A receptor antagonists. Though some azapirones are used as antipsychotics, all of the latter properties are generally undesirable in anxiolytics however, and further development has commenced to bring more selective of agents to the market.

Azapirones have fewer side effects than most other available anxiolytics like the benzodiazepines. Unlike benzodiazepines, azapirones are not addictive, do not cause cognitive/memory impairment, and do not induce significant tolerance or physical dependence.

[edit] List of Azapirones

Azapirone derivatives include:

As well as the following known metabolites:

[edit] Binding Profiles

A number of azapirones have been compared below:^[1]

They function as antagonists at all sites listed in which they have affinity for (< 100,000), with the exception of the 5-HT_1A receptor, where they act as partial agonists with varying intrinsic activity.

The values above are expressed as equilibrium dissociation constants. It should be noted that lower values correspond to higher binding at the site, or in other words, less is more.

[edit] References