Respiratory Medications Overview

Respiratory Medications

• Used to treat various respiratory conditions, including colds, allergies, asthma, and COPD.

Antihistamines

• Mechanism: Block histamine H1 receptors, reducing allergic reactions. Histamine is a chemical released during allergic responses.
• Effect: Reduce symptoms like sneezing, itching, congestion, runny nose.
• Types:
  • First-generation (e.g., diphenhydramine): Often cause sedation.
  • Second-generation (e.g., loratadine, cetirizine): Less likely to cause sedation.
• Examples: Diphenhydramine (Benadryl), loratadine (Claritin), cetirizine (Zyrtec).

Decongestants

• Mechanism: Stimulate alpha-adrenergic receptors (α1) in nasal blood vessels, causing vasoconstriction to reduce swelling.
• Effect: Relieve nasal congestion and improve airflow.
• Types:
  • Oral (e.g., pseudoephedrine): Can cause systemic side effects.
  • Topical (e.g., nasal sprays): May cause rebound congestion with prolonged use.
• Examples: Pseudoephedrine (Sudafed), phenylephrine, oxymetazoline (Afrin).

Antitussives (Cough Suppressants)

• Mechanism: Suppress the cough reflex.
• Types:
  • Central-acting: Inhibit cough center in the brain.
  • Peripheral-acting: Reduce airway irritation.
• Examples:
  • Dextromethorphan: Common, non-opioid.
  • Codeine: Opioid, used for more severe cases (with caution due to side effects and dependency risk).

Expectorants

• Mechanism: Increase mucus production and reduce mucus viscosity, facilitating clearing of mucus from the airways.
• Effect: Thins and loosens mucus, makes it easier to cough up.
• Example: Guaifenesin (Mucinex).
• Important Note: Staying hydrated enhances effectiveness.

Bronchodilators

• Relax airway muscles, making breathing easier.
• Used for asthma and COPD.

Beta-2 Adrenergic Agonists

• Mechanism: Stimulate beta-2 adrenergic receptors in the lungs, causing bronchodilation.
• Types:
  • Short-acting (SABA): Fast-acting, used in emergencies.
  • Long-acting (LABA): For long-term control.
• Examples: Albuterol (Salbutamol), Levalbuterol, Salmeterol, Formoterol.

Anticholinergics (Muscarinic Antagonists)

• Mechanism: Block muscarinic receptors, preventing bronchoconstriction.
• Types:
  • Short-acting (SAMA): For immediate relief.
  • Long-acting (LAMA): For long-term control.
• Examples: Ipratropium, Tiotropium, Aclidinium.

Corticosteroids

• Reduce airway inflammation in chronic conditions like asthma and COPD.
• Types:
  • Inhaled: For long-term management.
  • Oral/Systemic: For short-term flare-ups or severe cases.
• Examples: Fluticasone, Budesonide, Beclometasone (inhaled), Prednisone, Methylprednisolone (oral/systemic).

Leukotriene Modifiers

• Prevent bronchoconstriction, inflammation, and mucus production in asthma.

Leukotriene Receptor Antagonists (LTRAs)

• Mechanism: Block leukotriene receptors.
• Example: Montelukast (Singulair), Zafirlukast (Accolate).

5-Lipoxygenase Inhibitors

• Mechanism: Block 5-lipoxygenase, the enzyme that creates leukotrienes.
• Example: Zileuton (Zyflo).

Mast Cell Stabilizers

• Prevent histamine and other inflammatory mediator release from mast cells involved in allergic reactions.
• Examples: Cromolyn Sodium (Intal), Nedocromil (Tilade).

Phosphodiesterase-4 (PDE4) Inhibitors

• Primarily for severe COPD.
• Mechanism: Block PDE4, increasing cyclic AMP levels in inflammatory cells to reduce inflammation.
• Example: Roflumilast (Daliresp).

Immunomodulators (Biologics)

• Newer treatments for severe asthma. Target specific immune system components.

Monoclonal Antibodies

• Target specific cytokines or immune cells.
• Examples:
  • Anti-IgE: Omalizumab (Xolair)
  • Anti-IL-5: Mepolizumab (Nucala), Reslizumab
  • Anti-IL-4/IL-13: Dupilumab (Dupixent)

Additional Notes

• Important Considerations: Always consult with a healthcare professional before using any medication, especially for long-term use, and be aware of potential side effects.