Describe the pharmacodynamics.
All β2 adrenergic agonists selectively stimulate β2 adrenergic receptors.
Relax bronchial smooth muscle
List adverse effects.
Cardiac: ventricular arrhythmias, vasoconstriction, angina pectoris, tachycardia, and palpitations; may aggravate cardiomyopathy in patients with cardiovascular disease
Central nervous system/muscular: tremor, headache, anxiety, and sleep disturbances
Hypokalemia (risk of life-threatening arrhythmias): β2-mediated stimulation of Na+/K+-ATPase → intracellular K+ shift
Development of tolerance
Paradoxical bronchospasm may occur!
Bronchial asthma: used to achieve spasmolysis of the bronchi.
Acute exacerbation: use short-acting selective β2-agonists (e.g., albuterol)
Prophylaxis (in chronic disease): use long-acting selective β2-agonists (e.g., salmeterol)
COPD: used to achieve spasmolysis of the bronchi.
Preterm/undesired contractions in obstetrics: used for tocolysis
Hyperkalemia: Beta-2 adrenergic agonists drive K+ intracellularly.
Salmeterol should not be used as monotherapy during an acute asthma attack!
Absolute contraindication: hypersensitivity to β2 adrenergic agonists
Use with caution in patients with the following conditions:
Cardiovascular disease (e.g., heart failure, hypertension, arrhythmias, coronary artery disease)