Agonists anxiety disorders

Benzodiazepines, ie, the hiU BZR agonists, are prescribed for anxiety, insomnia, sedation, myorelaxation, and as anticonvulsants (97). Those benzodiazepines most commonly prescribed for the treatment of anxiety disorders are lorazepam (19), alprazolam (20), diazepam (21), bromazepam (22), chlorazepate (23), and oxazepam (24). These dmgs together represent about 70% of total... 

Anxiolytics are drugs used for the treatment of anxiety disorders. Apart from benzodiazpines, a frequently used anxiolytic is the 5HT1A (serotonin) receptor agonist buspiron, which has no sedative, amnestic or muscle-relaxant side effects, but whose action takes about a week to develop. Furthermore, it is less efficaceous than the benzodiazepines. Buspiron s mechanism of action is not fully understood. 

Benzodiazepines have a low risk for abuse in anxiety disorder patients without a history of alcohol or other substance abuse. Among the benzodiazepines there may be a spectrum of abuse liability, with drugs that serve as prodrugs for desmethyldiazepam (e.g., clorazepate), slow-onset agents (e.g., oxazepam), and partial agonists (e.g., abecarnil) having the least potential for abuse. However, there is no currently marketed benzodiazepine or related drug that is free of potential for abuse. 

Figure 19.8 A schematic representation of the GABAa receptor shift hypothesis. This proposes that patients with panic disorder have dysfunctional GABAa receptors such that the actions of drugs that behave as antagonists in normal subjects are expressed as inverse agonism in panic patients. It is unlikely that this theory extends to generalised anxiety disorder (GAD), for which benzodiazepine agonists are highly effective treatments, but it could explain why these drugs are relatively ineffective at treating panic disorder. (Based on Nutt et al. 1990)...

Buspirone (Buspar). The first nonsedating, nonbenzodiazepine specifically introduced as an anxiolytic, buspirone is FDA approved for the treatment of GAD. This medication acts as a partial agonist at the postsynaptic serotonin (5HT)-1A receptor. Like the antidepressants, buspirone has a delayed onset of action and effectively relieves the intrapsychic symptoms of GAD. Devoid of the muscle-relaxing properties of benzodiazepines, buspirone does not as effectively relieve the physical symptoms of GAD. Buspirone is not effective in the treatment of depression. Furthermore, its utility for the treatment of anxiety disorders other than GAD appears to be limited. 

Aripiprazole Partial agonist of 11 Serotonin-2A Anxiety disorders Psychotic disorders... 

Ballenger, J.C., McDonald, S., Noyes, R., Rickels, K., Sussman, N., Woods, S., Patin, J., and Singer, J. (1991) The first double-blind, placebo-controlled trial of a partial benzodiazepine agonist abe-carnil (ZK 112—119) in generalized anxiety disorder. Psycho-pharmacol Bull 27 171-179. 

Generalized anxiety disorder is still considered the gold standard indication for benzodiazepines (P. J. Perry et al. 1990]. However, buspirone, a serotonin-la partial agonist, has been demonstrated as effective in this disorder... 

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