Drugs interacting directly with adrenoceptors

Drugs interacting directly with adrenoceptors

An overview of the receptors of the Sympathetic Nervous system is provided by the Guide to PHARMACOLOGY and further information about the actions associated with these receptors and their potential as therapeutic targets is available here

Drugs that directly interact with adrenoceptors can act as agonists (thereby mimicking some of the actions of the sympathetic nervous system) or antagonists (blocking the effects of sympathetic activation).  The actions of these drugs will be dependent on their selectivity profile for the different adrenoceptor subtypes as well as their interaction with removal systems (e.g. uptake 1; metabolism by monoamine oxidase (MAO)/catechol-O-methyltransferase (COMT).

For example, adrenaline can activate all adrenoceptor subtypes so will stimulate β1-adrenoceptors to increase the rate and force of cardiac contraction, cause vasoconstriction in the viscera and skin via stimulation of a1-adrenoceptors, but vasodilatation in skeletal muscle vascular beds due to stimulation of β2- adrenoceptors. Activation of β2- adrenoceptors in the lungs results in bronchodilation.  These effects together make adrenaline useful treatment for the treatment of anaphylactic shock.  However, adrenaline must be given via injection as it is not orally active and has a short half life.

Examples of therapeutic uses of drugs acting at adrenoceptors are given in the table below.

Some therapeutic actions of drugs acting at adrenoceptors.



Therapeutic use


α1- adrenoceptor agonists vasoconstriction nasal decongestants, ocular decongestants phenylephrine
α2-adrenoceptor antagonists decrease intraocular pressure treatment of glaucoma clonidine
α1-adrenoceptor antagonists vasodilation antihypertensives prazosin; terazosin
relaxation of bladder neck and prostate symptomatic treatment of Benign Prostatic Hyperplasia terazosin; tamsulosin (uroselective)
ßadrenoceptors agonists bronchodilatation treatment of asthma salbutamol (albuterol)
ßadrenoceptors agonists relaxation of uterine smooth muscle delay pre-term labour terbutaline
ß1-adrenoceptor antagonists

decrease cardiac activity & decrease blood pressure

antihypertensives atenolol

Adrenoceptors online

This website provides information about alpha and beta adrenoceptors – including subtypes, location, function and transduction mechanisms.

Average: 2 (3 votes)

Adrenergic pharmacology videos

This is a series of videos of mini lectures in adrenergic pharmacology.  The videos are well paced and with easy to follow slides.  Included at the end are some challenge questions. 

Average: 4.1 (7 votes)