Beta-2 Agonists (Albuterol, Salmeterol)

Summary

Inhaled beta-2 agonists include the fast-acting albuterol and the slow-acting salmeterol. Both of these drugs are used to treat asthma and COPD. Side effects include tremors, tachycardia, hypokalemia, and CNS stimulation.

Key Points

• Inhaled Beta-2 Adrenergic Agonists
  • Key Drugs
    • Albuterol
    • Salmeterol
    • Formoterol
    • Levalbuterol
    • Terbutaline (given IV, not inhaled)
  • Mechanism
    • Activate beta-2 adrenergic receptors in the lungs, relaxing the bronchial smooth muscle and causing bronchodilation
  • Clinical Use
    • Asthma
      • Albuterol= acute asthma attacks, short acting
      • Salmeterol = long-term control, long-acting
    • COPD exacerbations (albuterol)
    • Exercise-induced bronchospasm (albuterol)
      • Albuterol can be taken before exercise to prevent exercise-induced bronchospasm
  • Administration
    • Inhaler
      • Shake the medication canister prior to administration
      • A spacer may be used to improve drug delivery to the lung and reduce undesirable side effects
      • When a client is prescribed both a beta-2 agonist and an inhaled glucocorticoid, the beta-2 agonist should be administered first
        • The beta-2 agonist will open the bronchioles, allowing for better absorption of the glucocorticoid
      • Salmeterol inhalers are used every 12 hours for long-term control. They are not used to treat an acute asthma attack.
  • Side Effects and Adverse Reactions
    • Tremors
      • Most common side effect, expected
      • In addition to beta-2 receptors in the lungs, these medications also activate the beta-2 receptors in the skeletal muscle, causing tremors
      • Will usually diminish over time
    • Tachycardia / Palpitations
      • Oral beta-2 adrenergic agonists may also activate the alpha-1 receptors in the heart, causing tachycardia, angina, hypertension, and palpitations
      • Patients should avoid caffeine
      • If this occurs, dosage might need to be reduced
      • Contraindicated in patients with arrhythmia
    • Hypokalemia
      • Albuterol increases potassium uptake by the cells, thus decreasing the amount of potassium in the blood
    • CNS Stimulation
      • Restlessness, agitation, Anxiety, Excitability, Nervousness, Insomnia
    • Hyperglycemia
      • Use with caution in diabetic patients - they may require more insulin than normal