• Clinical science

Antiadrenergic agents

Abstract

Antiadrenergic agents inhibit the activity of the sympathetic nervous system. They act by blocking adrenergic receptors in target organs or by inhibiting the synthesis, storage, or release of endogenous catecholamines (mainly norepinephrine). This class of medications is most commonly used for the treatment of ischemic heart disease and hypertension, although antiadrenergic agents may also be used for urinary retention secondary to benign prostatic hyperplasia and for psychiatric conditions such as anxiety disorders and post-traumatic stress disorder.

Beta blockers are discussed in detail in a separate learning card.

General mode of action

All antiadrenergic agents reduce sympathetic tone by inhibiting the production, storage, or release of catecholamines (especially norepinephrine).

All drug groups that directly inhibit the sympathetic nervous system (i.e., alpha blockers, beta blockers, and drugs that reduce sympathetic tone) are treatment options for arterial hypertension!
References:[1][1][2][3][4][5][6][7][8]

Alpha blockers

Indication Side effects
Doxazosin
Terazosin
Tamsulosin
Alfuzosin
Silodosin
Prazosin
Phenoxybenzamine
  • Same as alpha blockers above
  • In addition: pronounced reflex tachycardia

Alpha blockers are usually only second-line drugs for the treatment of hypertension, since they do not improve prognosis!References:[1][9]

Alpha-2 adrenergic agonists

Indication Side effects
Clonidine
Methyldopa
Tizanidine
Guanfacine
Dexmedetomidine
  • Sedation

Sympathetic blockers are usually used in antihypertensive combination regimens!

References:[1][4][10][11][12][13][14]