Benzodiazepine derivatives antianxiety effects

The benzodiazepine derivatives class of antianxiety agents shares the property of binding to a benzodiazepine receptor, part of the GABA receptor-chloride channel complex whose function it modulates allosterically. Not only the anxiolytic effects of the benzodiazepines, but also the anticonvulsant, sedative, or muscle relaxant effects seem to be mediated by the GABA-related mechanism. Besides the direct involvement of the GABA system, in parallel or more downstream to this, several other neurotransmitters such as serotonin have been suggested to participate in different aspects of benzodiazepine action. 

Benzodiazepines may depict two- or three-compartment disposition kinetics. For example, a benzodiazepine derivative given in a suitable dose at night may impose dose-dependent effects, in that the concentration attained at night may be in the hypnotic range, whereas the concentration of the drug or its active metabolite or metabolites during the following day may be sufficient to produce antianxiety effects. 

Prazepam, a benzodiazepine derivative (30 mg p.o. daily in divided doses), is indicated in the management of anxiety disorders and for the short-term relief of the symptoms of anxiety. It depresses the CNS at the hmbic and subcortical levels of the brain. It produces an antianxiety effect by enhancing the effect of the neurotransmitter GABA on its receptor in the ascending reticular activating system, which increases inhibition and blocks both cortical and limbic arousal. 

---