Asthma, Known or New Diagnosis Clinical Pathway — Medication Guidance: Mechanism of Action, Side Effects, and Comments — Primary Care

Known or Suspected Asthma Clinical Pathway — Primary Care

Medication Guidance

Mechanism of Action, Side Effects, and Comments

Short-acting Beta2 Agonists (SABA)
  • Albuterol
  • Levalbuterol
  • Mechanism: binds to beta2 adrenergic receptor, resulting in bronchodilation
  • Side effects: tachycardia, palpitations, tremors, hypokalemia
  • Comments:
    • There is no difference in efficacy or safety (including differences in heart rate) between albuterol and levalbuterol when administered at equipotent doses
      • Albuterol:levalbuterol dose ratio is 2:1
    • Albuterol 0.083% is preferred over 0.5% because it does not require further dilution
    • If prescribing albuterol 0.5% solution, order 0.9% NaCl nebs to dilute to a total volume of 3 mL
Anticholinergics
  • Ipratropium bromide
  • Mechanism: inhibits muscarinic cholinergic receptors, resulting in bronchodilation; reduces vagal tone of airways and blocks reflex bronchoconstriction secondary to irritants; may decrease mucus-gland secretion
  • Side effects: dry mouth, blurred vision if sprayed in eyes
  • Comments:
    • Not used for EIB
    • Alternative agent for patients who do not tolerate SABAs (less cardiac stimulation)
Systemic Corticosteroids
  • Methylprednisolone
  • Prednisone/Prednisolone
  • Dexamethasone
  • Mechanism: anti-inflammatory
  • Side effects: hypertension, irritability, gastritis, hyperglycemia, fluid retention, increased appetite
  • Comments:
    • No need to taper courses < 10 days
    • Start maintenance dose 12 hrs after initial prednisone loading dose or 24 hrs if dexamethasone given
      as initial dose
    • Dexamethasone tablets preferred over solution due to better palatability
    • Consider dexamethasone x2 doses every 24-48 hrs apart instead of prednisone 5 day with concerns
      for compliance

Long-term Control Medications

Inhaled Corticosteroids (ICS)
  • Mechanism: anti-inflammatory, reverses beta2-receptor downregulation
  • Side effects: cough, dysphonia, oral thrush, growth velocity suppression (~1 cm with low to medium doses), reduced bone density with high doses
  • Comments:
    • Encourage use of spacers (breath-activated dosage forms are not compatible with spacers)
    • Counsel patients to rinse mouth and spit after use to prevent thrush
    • Budesonide is the only ICS available in nebulized form
Long-acting Beta2 Agonists (LABA)
  • Formoterol
  • Salmeterol
  • Mechanism: binds to beta2 adrenergic receptor, resulting in bronchodilation
  • Side effects: tachycardia, palpitations, tremors, hypokalemia; QTc prolongation with overdoses
  • Comments:
    • Do not prescribe LABA as single drug; prescribe as a combination product with ICS only
    • Slower onset of action (15-30 mins) and longer duration of action (< 12 hrs) compared to SABAs
    • If stepping up therapy to include combination LABA/ICS, consider prescribing separate inhaler (ICS only) if part of Asthma Action Plan for acute flares
Leukotriene Receptor Antagonists (LTRAs)
  • Montelukast
  • Mechanism: Blocks inflammatory effects of leukotriene in the airway
  • Side effects: behavior or mood-related changes
  • Comments: Do not use LTRA + LABA as substitute for ICS + LABA
Immunomodulators
  • Omalizumab
  • Mepolizumab
  • Benralizumab
  • Dupilumab
  • Mechanism:
    • Omalizumab: prevents binding of IgE to receptors on basophils and mast cells
    • Benralizumab and Mepolizumab: interleukin-5 receptor antagonist; reduces eosinophil production and survival
    • Dupilumab: interleukin-4 receptor antagonist; inhibits cytokine-induced inflammatory responses
  • Side effects: pain and bruising at injection site (subcutaneous)
  • Comments:
    • Consider in patients with severe persistent asthma and allergies; consult Allergy
    • Patients must be monitored for anaphylaxis following injection

Reference

NAEPP 2020 Guidelines