Asthma Medications

Bronchodilator Medications

• MDI Formulation: Epinephrine (Epi) delivers 0.22 mg/puff with a duration of action of 1-3 hours.
• Racemic Epinephrine: Contains S-2 and is available in SVN 2.25% solution (0.25-0.5 ml, 5-11 mg, given qid).
  • Onset: 3-5 minutes, Peak effect: 5-20 minutes, Duration: 0.5-2 hours.
• Metaproterenol (Alupent): A β2 agonist available as SVN (0.4-0.6% solution, tid/qid), tablets (10-20 mg, tid/qid), and syrup (10 mg/5 ml).
  • Onset: 1-5 minutes, Peak: 60 minutes, Duration: 2-6 hours.
• Albuterol (Proventil, Ventolin HFA): Another β2 agonist; SVN 0.5% solution (1.25 or 2.5 mg tid/qid), MDI (90 mcg/puff, 2 puffs tid/qid), tablets (2, 4, 8 mg bid, tid, qid).
  • Onset: 15 minutes, Peak: 30-60 minutes, Duration: 5-8 hours.
• Pirbuterol (Maxair): MDI formulation (200 mcg/puff, 2 puffs q4h).
  • Onset: 5 minutes, Peak: 30 minutes.

Inhaled Anticholinergic Bronchodilators

• Ipratropium Bromide: Affects M1, M2, and M3 receptors.
  • Dosage: HFA MDI (17 mcg/puff, 2 puffs qid), SVN (0.02% solution, 500 mcg tid/qid), nasal spray (21-42 mcg, 2-4 times daily).
  • Onset: 15 minutes, Peak: 1-2 hours, Duration: 4-6 hours.
• Ipratropium and Albuterol Combination: Contains 18 mcg/puff of ipratropium and 90 mcg/puff of albuterol.
  • Onset: 15 minutes, Peak: 1-2 hours, Duration: 4-6 hours.
• Tiotropium Bromide: Highly selective for M3.
  • Dosage: SVN (Ipratropium 0.5 mg and albuterol 2.5 mg), DPI (18 mcg/inhalation, 1 inhalation daily).
  • Onset: 30 minutes, Peak: 1-3 hours, Duration: 24 hours.

Mechanism of Action

• Anticholinergic bronchodilators block acetylcholine at muscarinic receptors in bronchial smooth muscles, reducing mucus production.

Mucolytics and Mucokinetics

• Mucolytic Agents: Disrupt chemical bonds in mucoproteins, liquefying mucus for easier removal.
  • Examples: N-Acetylcysteine (NAC), Dornase Alpha (Pulmozyme), Hyperosmolar saline.
• Expectorants: Increase secretions and decrease mucus viscosity, facilitating easier sputum removal.

Adverse Effects of Mucolytics

• Notable side effects include nausea, vomiting, hypersensitivity, rash, fever, and bronchospasm risk in asthmatics.

Corticosteroids (Anti-inflammatories)

• Used to treat inflammation, allergies, asthma, and arthritis.
• Can be endogenous (produced by the body) or exogenous (prescribed when body levels are low).

Adverse Effects of Corticosteroids

• General effects from systemic corticosteroids include immunosuppression, fluid retention, and increased blood sugar.
• Specific effects of aerosolized steroids include dysphonia, cough, and risk of local infections.

Non-Steroidal Anti-inflammatory Anti-asthma Drugs

• Types:
  • Cromolyn-like agents (Mast Cell Stabilizers; e.g., Cromolyn Sodium).
  • Antileukotrienes (e.g., Montelukast).
  • Monoclonal antibody (e.g., Omalizumab).
• Mechanism: Cromolyn Sodium inhibits mast cell degranulation and histamine release. Antileukotrienes block leukotriene receptor activity.

Indications of Cromolyn Sodium

• Serves as a prophylactic treatment for asthma, preventing attacks in individuals with bronchial asthma.

Allergy Mechanism

• Allergic reactions involve B cells producing IgE antibodies upon initial allergen exposure, which attach to mast cells. During re-exposure, these mast cells release histamine, causing local inflammation and respiratory issues.
• Severe systemic reactions are termed anaphylaxis, which can be life-threatening.