Alpha blocker

Alpha-blockers or α-blockers are pharmacological agents that act as neutral antagonists or inverse agonists of α-adrenergic receptors (α-adrenoceptors).^[1]

Classification

• α₁-blockers act on α₁-adrenoceptors
• α₂-blockers act on 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.

Examples of non-selective α-adrenergic receptor antagonists include:

• Phenoxybenzamine
• Phentolamine
• Tolazoline
• Trazodone
• Typical and atypical antipsychotics

Selective α₁-adrenergic receptor antagonists include:

• Alfuzosin^[2]
• Doxazosin^[3]
• Prazosin (inverse agonist)^[4]
• Tamsulosin^[5]
• Terazosin^[6]
• Silodosin^[7]

Selective α₂-adrenergic receptor antagonists include:

• Atipamezole
• Idazoxan
• Mirtazapine
• Yohimbine

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.^[8]

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).

See also

• Beta blocker

References