Anxiety disorders benzodiazepines

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 are amongst the most frequently prescribed drugs they have well-established uses in the treatment of anxiety disorders (anxiolytics) and insomnia, preanaesthetic sedation, suppression of seizures, and muscle relaxation. 

The definition of desired therapeutic and side effects in the case of the benzodiazepines very much depends on the clinical problem in question. The sedative and hypnotic actions are desired effects in the treatment of insomnia, but undesired effects in the treatment of anxiety disorders. Effects that are usually undesired include daytime drowsiness, potentiation of the sedative effects of ethanol, and anterograde amnesia. They are mediated via the benzodiazepine site of GABAa receptors, since they can be antagonized with flumazenil. 

Tranquilizers (also called antianxiety drugs) are used to treat a variety of psychiatric disorders which go along with anxiety (anxiety disorders). Serotonin-reuptake inhibitors and the benzodiazepines are the most commonly employed drugs for the treatment of common clinical anxiety disorders. 

Iwata N, Cowley DS, Radel M, et al Relationship between a GABA alpha g Pro385Ser substitution and benzodiazepine sensitivity. Am] Psychiatry 156 1447—1449,1999 Jacobson AF, Dominguez RA, Goldstein B, et al Comparison of buspirone and diazepam in generalized anxiety disorder. Pharmacotherapy 5 290—296, 1985 Jaffe JH, Ciraulo DA, Nies A, et al Abuse potential of halazepam and diazepam in patients recently treated for acute alcohol withdrawal. Clin Pharmacol Ther 34 623-630, 1983... 

Anxiety disorders are common in the population of opioid-addicted individuals however, treatment studies are lacking. It is uncertain whether the frequency of anxiety disorders contributes to high rates of illicit use of benzodiazepines, which is common in methadone maintenance programs (Ross and Darke 2000). Increased toxicity has been observed when benzodiazepines are co-administered with some opioids (Borron et al. 2002 Caplehorn and Drummer 2002). Although there is an interesting report of clonazepam maintenance treatment for methadone maintenance patients who abuse benzodiazepines, further studies are needed (Bleich et al. 2002). Unfortunately, buspirone, which has low abuse liability, was not effective in an anxiety treatment study in opioid-dependent subjects (McRae et al. 2004). Current clinical practice is to prescribe SSRIs or other antidepressants that have antianxiety actions for these patients. Carefully controlled benzodiazepine prescribing is advocated by some practitioners. 

Medical use of benzodiazepines has been declining. Prescribing trends show an overall decline in the number of all benzodiazepine prescriptions written, with a market shift to increased prescribing of short elimination half-life agents (lorazepam, alprazolam), compared with long-elimination half-life agents (diazepam, chlordiazepoxide) (Ciraulo et al. 2004). In 2001, alprazolam was the most widely prescribed benzodiazepine (Ciraulo et al. 2004), and it also was the most widely prescribed psychiatric medication in that year for mood and anxiety disorders (Stahl 2002). 

Lejoyeux et al. 1998). Similar to opioid-dependent persons, these patients reported that they use benzodiazepines to self-medicate anxiety, insomnia, and alcohol withdrawal and, less commonly, to enhance the effects of ethanol. Approximately l6%-25% of patients presenting for treatment of anxiety disorders abuse alcohol (Kushner et al. 1990 Otto et al. 1992). Controversy exists concerning appropriate benzodiazepine prescribing in this population (Cir-aulo and Nace 2000 Posternak and Mueller 2001). 

Pharmacodynamic tolerance to the psychomotor effects of benzodiazepines has been demonstrated after single or multiple doses (File 1985 Greenblatt and Shader 1978 Rosenberg and Chiu 1985). Pharmacodynamic tolerance to the anxiolytic effect (over a 6-month period) has not been demonstrated (Rickels et al. 1983), and clinical experience supports the view that many patients with anxiety disorders require long-term therapy with benzodiazepines or alternative antianxiety agents. An important clinical consequence of tolerance to sedative effects is observed in benzodiazepine overdoses, when patients may initially be... 

Not cross-tolerant to benzodiazepines and should not be used for acute withdrawal high doses may be used to treat anxiety disorders to help maintain long-term discontinuation after abstinence has been achieved. 

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. 

Fyer AJ, Liebowitz MR, Gorman JM, et al Effects of clonidine on alprazolam discontinuation in panic patients a pilot study. J Clin Psychopharmacol 8 270—274,1988 Garvey MJ, Tollefson GD Prevalence of misuse of prescribed benzodiazepines in patients with primary anxiety disorder or major depression. Am J Psychiatry 143 1601-1603, 1986... 

Mueller TI, Goldenberg IM, Gordon AL, et al Benzodiazepine use in anxiety disordered patients with and without a history of alcoholism. J Clin Psychiatry 57 83-89, 1996... 

Posternak MA, Mueller TI Assessing the risks and benefits of benzodiazepines for anxiety disorders in patients with a history of substance abuse or dependence. Am J Addict 10 48-68, 2001... 

Generalized anxiety disorder has been relatively neglected from the point of view of both health economics and pharmacoeconomics. The changing diagnostic criteria have made it difficult to compare data over time, leading researchers to focus on the more clearly defined disorders such as panic and obsessions. Drug treatment has been dominated by the benzodiazepines, usually available genetically and cheaply. However, as the final section of this chapter will show, all this is in flux. 

An Australian study compared medical utilization and costs in patients with panic disorder, those with social anxiety disorder, and a control group (Rees et al, 1998). Almost half of the panic disorder patients had seen a primary-care physician more than seven times over a 6-month period, compared with 7% of the social phobic patients and none of the control group. The mean costs were A 150, A 60 and A 20 respectively. The patients with panic disorder were treated with antidepressants (39%), benzodiazepines (15%), relaxants (12%), beta-blockers (7%) and other medication (7%). Twenty per cent received no medication. Patients with panic... 

The pharmacoeconomics of the anxiety disorders has received litde attention. In the past drug costs were largely incurred by use of benzodiazepines, most of which are available in generic forms and are cheap. They are effective and acceptable in the short term. Long-term use is associated with the risk of physical dependence, with an adverse risk—benefit ratio and high cost terms to facilitate withdrawal. There is now a trend towards the use of antidepressants in the anxiety disorders. Clinical experience has been followed by formal trial evaluation. 

Tricyclic antidepressants are not licensed for use in the anxiety disorders, so in theory the SSRIs should not be compared with them in cost-effectiveness terms. The SSRIs and venlafaxine are supplanting benzodiazepines as the latter s long-term problems become more appreciated. The SSRIs will take an increasing proportion of the market. However, in comparison with the overall costs of the anxiety disorders, this drug expenditure can be justified. Further cost-offset and cost-effectiveness studies will help hammer this point home. 

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)...

Benzodiazepines are recommended for acute treatment of generalized anxiety disorder when short-term relief is needed, as an adjunct during initiation of antidepressant therapy, or to improve sleep. 

The dose of benzodiazepine required for improvement in panic disorder generally is higher than that used in other anxiety disorders. 

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