In-Depth Notes on Respiratory Pharmacology

Understanding Pharmacology for Health Professionals - Respiratory Drugs

Learning Objectives

  • 6.1 Identify drug categories used to treat respiratory diseases.

  • 6.2 Identify the common suffixes of generic drugs for those drug categories.

  • 6.3 Compare and contrast the therapeutic effects of those drug categories.

  • 6.4 Given the generic name of a respiratory drug, identify its trade name(s) and drug category.

  • 6.5 Given the trade name of a common respiratory drug, identify its drug category and the diseases/symptoms it treats.

  • 6.6 Demonstrate mastery of the chapter by completing the Chapter Review Exercises.

Upper Respiratory System Overview

  • Located in the head and neck.

  • Components:

  • Sinuses

  • Nose

  • Throat (pharynx)

  • Common conditions affecting the upper respiratory system:

  • Sinus congestion

  • Nasal allergies

  • Cough

Allergen-Specific Immunotherapy Drugs

  • Allergens are substances triggering allergic reactions.

  • Allergy shots:

  • Prepared from liquid extracts containing allergens.

  • Injected subcutaneously with progressively stronger extracts.

  • Allergen-specific immunotherapy:

  • Alternative method taken orally.

  • Provides immunotherapy for limited allergens.

  • Dose is measured as the Index of Reactivity (e.g., extracted pollens in sublingual tablets).

Antihistamine Drugs

  • Histamine Release:

  • Triggered by immune response; causes vasodilation, swelling, and irritation.

  • Therapeutic Effects:

  • Block histamine receptors to reduce symptoms in nasal and throat mucous membranes.

  • Types:

  • First-generation: Effective but causes drowsiness (e.g., Benadryl).

  • Second-generation: Non-sedating due to different chemical structure (e.g., Claritin, Astepro).

Antitussive Drugs

  • Function:

  • Suppress cough center in the brain and anesthetize stretch receptors in the upper respiratory tract.

  • Types:

  • Non-opioid: Benzonatate (R), Dextromethorphan (OTC).

  • Opioid: Contain codeine; used for severe cough, sometimes combined with guaifenesin.

  • Combination Drugs: May include expectorants and decongestants.

Corticosteroid Drugs

  • Mechanism:

  • Decrease inflammatory response, edema of mucous membranes; do not have decongestant or antihistamine effects.

  • Forms:

  • Intranasal corticosteroids: Treat allergic/non-allergic rhinitis (e.g., Beclomethasone, Mometasone).

  • Common suffixes: -lone, -sone, -sonide.

Decongestant Drugs

  • Mechanism:

  • Vasoconstrictors reducing blood flow to mucous membranes. Stimulate alpha receptors to decrease swelling and relieve stuffiness.

  • Forms:

  • Topical sprays (e.g., Afrin, oxymetazoline) and oral medications (e.g., phenylephrine).

  • Commonly used for colds and allergies.

Mast Cell Stabilizer Drugs

  • Function:

  • Stabilize mast cell membranes to prevent histamine release; reduce edema and sneezing.

  • Example: Cromolyn (NasalCrom).

Lower Respiratory System Overview

  • Located in neck and thoracic cavity.

  • Components:

  • Larynx

  • Trachea

  • Bronchi

  • Bronchioles

  • Lungs

  • Common conditions:

  • Asthma

  • Chronic Obstructive Pulmonary Disease (COPD)

  • Influenza

  • Tuberculosis

Drugs for Asthma

  • Asthma: Disorder characterized by reactive airway disease, inflammation, edema, and bronchoconstriction.

  • Main Drug Types:

  • Bronchodilators: Relax smooth muscle (e.g., Albuterol, Tiotropium).

  • Corticosteroids: Reduce inflammation (e.g., Ciclosonide, Mometasone).

  • Leukotriene Blockers: Block leukotriene action to prevent inflammation (suffix -lukast).

  • Monoclonal Antibodies: Inhibit interleukin action; administered by injection (suffix -mab).

Chronic Obstructive Pulmonary Disease (COPD) Drugs

  • Components:

  • Chronic bronchitis and emphysema.

  • Drug Classes:

  • Anticholinergics: Relax and dilate bronchioles.

  • Bronchodilators: Mimic epinephrine action to dilate bronchioles.

  • Corticosteroids: Similar to asthma treatment to reduce inflammation.

  • Expectorants: Help clear mucus (e.g., Guaifenesin).

Drugs for Coronary Disease (COVID-19)

  • COVID-19 Overview:

  • Viral illness, symptoms include cough, shortness of breath.

  • Treatment includes Dexamethasone (corticosteroid), Remdesivir (antiviral), and monoclonal antibodies.

Influenza Treatment

  • Caused by a virus; prevent and treat with medications like Tamiflu and Baloxavir.

  • Vaccination remains the best preventive measure.

Antitubercular Drugs

  • Treat infections caused by Mycobacterium tuberculosis; must be a combination therapy over an extended period (usually 9 months) to combat resistance.

Smoking Cessation Drugs

  • Nicotine Replacement: Available as patches, gum, lozenges, sprays.

  • Other Options:

  • Bupropion: Antidepressant aiding cravings.

  • Varenicline (Chantix): Blocks nicotine receptor activation.