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.