Alpha blocker
Alpha-blockers, α-blockers, or α-adrenergic-antagonists are pharmacological agents that act as receptor antagonists of α-adrenergic receptors (α-adrenoceptors).[1]
Contents
Classification
- α1-blockers or antagonists act at α1-adrenoceptors
- α2-blockers or antagonists act at α2-adrenoceptors
When the term "alpha blocker" is used without further qualification, it sometimes refers to α1-blockers, and sometimes refers to agents that act at both types of receptors.[citation needed]
Examples of non-selective α-adrenergic blockers include:
- Phenoxybenzamine
- Phentolamine
- Tolazoline
- Trazodone
- Typical and atypical antipsychotics
Selective α1-adrenergic blockers include:
Selective α2-adrenergic blockers include:
The agents carvedilol and labetalol are both α- and β-blockers.
Uses
α-Blockers are used in the treatment of several conditions, such as Raynaud's disease, hypertension, and scleroderma.[2]
α-Blockers can also be used to treat anxiety and panic disorders, such as generalized anxiety disorder, panic disorder, or posttraumatic stress disorder (PTSD). While most commonly used to treat hypertension (usually in conjunction with diuretics when other treatments are ineffective), they are also often used to treat the symptoms of BPH (benign prostatic hyperplasia).
Prazosin is an alpha1-receptor antagonist. Raskind and colleagues[3] studied the efficacy of prazosin for PTSD among Vietnam combat veterans in a 20-week double-blind crossover protocol with a two-week drug washout to allow for return to baseline.[3] The CAPS and the Clinical Global Impressions-Change scale (CGI-C) were the primary outcome measures. Patients who were taking prazosin had a robust improvement in overall sleep quality (effect size, 1.6) and recurrent distressing dreams (effect size, 1.9). In each of the PTSD symptom clusters the effect size was medium to large: 0.7 for reexperiencing or intrusion, 0.6 for avoidance and numbing, and 0.9 for hyperarousal. The reduction in CGI-C scores (overall PTSD severity and function at endpoint) also reflected a large effect size (1.4). Prazosin appears to have promise as an effective treatment for PTSD-related sleep disturbance, including trauma-related nightmares, as well as overall Anxiety and PTSD symptoms.
See also
References
- ↑ alpha-Adrenergic Blockers at the US National Library of Medicine Medical Subject Headings (MeSH)
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Raskind MA, Peskind ER, Kanter ED, et al: Reduction of nightmares and other PTSD symptoms in combat veterans by prazosin: a placebo controlled study. American Journal of Psychiatry 160:371–373, 2003[Abstract/Free Full Text]
