Asthma Medications: Corticosteroids and Beta Agonists

Corticosteroids

• Have been used to treat asthma since 1950
• Have broad anti-inflammatory efficacy
• Inhibit production of inflammatory cytokines
• Do not relax airway smooth muscle directly
• ↓bronchial reactivity and frequency of asthma exacerbations when taken regularly
• Have an effect on airway obstruction due to:
  • Contraction of engorged vessels in the bronchial mucosa
  • Potentiation of the effects of β-receptor agonists
  • Inhibition of lymphocytic, eosinophilic mucosal inflammation of asthmatic airways

β2 Agonists

• Formoterol: full agonist with an onset of action similar to albuterol
• Salmeterol: partial agonist with an onset of action of ~ 30 minutes
• Indacaterol, Olodaterol, Vilanterol, and Bambuterol: ultralong acting β agonists, need to be taken only once a day
• Cause prolonged bronchodilation, but do not relax airway smooth muscle directly
• Should be used in combination with an ICS for asthma treatment

Methylxanthines

• Theophylline: chronically used, slightly ↓ overall level of bronchial reactivity
• No effect on airway smooth muscle tone, ineffective in reversing asthmatic bronchospasm
• Only of value when taken prophylactically

Monoclonal Antibody

• Anti-IgE: omalizumab (Xolair)
• Prevents binding of IgE to mast cells and basophils
• ↓release of mediators following allergen exposure
• Alternative to initial ICS therapy, but not as effective
• Doses: for moderate-severe allergic asthma not well controlled by CS, ≥ 6 years old, and moderate to severe persistent asthma

Leukotriene Antagonists

• Leukotrienes result from the action of 5-lipoxygenase on arachidonic acid
• Synthesized by inflammatory cells in the airways, including eosinophils, mast cells, macrophages, and basophils
• Leukotriene receptor antagonists (LTD4-receptor antagonists):
  • Zafirlukast (Accolate): oral, twice daily
  • Montelukast (Singulair): oral, once daily
• 5-lipoxygenase inhibitor: Zileuton (Zyflo): oral, 4x daily (not commonly used)
• Use: improve FEV1, decrease asthma symptoms, rescue drug use, and exacerbations due to asthma

Other Therapies

• Allergen Immunotherapy:
  • Treatment option where allergy plays a prominent role, including asthma with allergic rhino-conjunctivitis
  • 2 approaches: Subcutaneous immunotherapy (SCIT) and Sublingual (SLIT)
  • Most common allergens included: house dust mite and grass pollens
• Vaccines
• Oxygen
• Pulmonary rehabilitation
• Surgery