Adrenergic beta-Agonists
Overview
Overview
Beta agonists activate beta-adrenergic receptors. Their effects range from cardiac stimulation to bronchodilation and detrusor relaxation according to beta-1, beta-2 or beta-3 selectivity.
Classification
Classification
The main groups are beta-1-predominant inotropes, short- and long-acting beta-2 bronchodilators, beta-3 agonists for overactive bladder and nonselective beta agonists such as isoproterenol.
Mechanism of action
Mechanism of action
All beta receptors couple mainly to Gs and increase cyclic AMP. In the heart this increases rate and contractility; in many smooth muscles cyclic AMP promotes relaxation.
Important members
Important members
Dobutamine is beta-1 predominant; salbutamol, terbutaline, formoterol and salmeterol are beta-2 agonists; mirabegron and vibegron are beta-3 agonists; isoproterenol stimulates beta-1 and beta-2.
Clinical uses
Clinical uses
Uses include short-term inotropic support, bronchospasm relief, maintenance bronchodilation, selected bradyarrhythmias, overactive bladder and limited obstetric use of beta-2 agonists.
Adverse effects
Adverse effects
Tachycardia, palpitations, arrhythmia, tremor, anxiety, hyperglycaemia and hypokalaemia may occur. Beta-3 agonists can increase blood pressure and may contribute to urinary retention.
Contraindications and precautions
Contraindications and precautions
Use cautiously in tachyarrhythmia, unstable ischaemic heart disease, uncontrolled hypertension and severe hypokalaemia. Long-acting beta-2 therapy in asthma must follow controller-treatment recommendations.
References
- Ashkar H, Adnan G, Makaryus AN. Dobutamine. NCBI Bookshelf. Updated 2024. SOURCE:NCBI:DOBUTAMINE:2024
- Hsu E, Bajaj T. Beta2-Agonists. NCBI Bookshelf. Updated 2023. SOURCE:NCBI:BETA2_AGONISTS:2023
- Dawood O, El-Zawahry A. Mirabegron. NCBI Bookshelf. Updated 2023. SOURCE:NCBI:MIRABEGRON:2023