NR 293 Pharmacology Exam 1
Student Name
Chamberlain University
NR-293: Pharmacology for Nursing Practice
Prof. Name
Date
Week 3: Gas Exchange and Bronchodilators
Introduction to Bronchodilators
Optimal gas exchange begins with a thorough respiratory assessment, enabling the nurse to prioritize interventions appropriately. Bronchodilators play a central role in pharmacotherapeutic strategies for respiratory conditions. These medications enhance breathing by widening the airways, easing mucus clearance, and minimizing inflammation. Depending on the formulation, they may act as single agents or as part of combination therapies with synergistic effects. Administration order is also significant—some drugs are taken first to open airways, improving the effectiveness of subsequent medications.
Conditions Managed with Respiratory Medications
Respiratory medications are prescribed to address a range of acute and chronic conditions, such as:
- Seasonal allergies and hay fever
- Asthma
- Chronic obstructive pulmonary disease (COPD)
- Emphysema
- Chronic bronchitis
These medications can target inflammation, relax smooth muscles, reduce secretions, and control allergic responses.
Rescue Inhalers and Drug Classifications
Short-acting inhaled beta2-adrenergic agonists are recommended as “rescue” inhalers to relieve sudden episodes of breathlessness rather than for daily maintenance. In clinical practice, respiratory drugs are categorized according to their primary therapeutic effect.
| Classification | Examples | Primary Uses |
|---|---|---|
| Bronchodilators | Albuterol, Levalbuterol | Relief of asthma and COPD symptoms |
| Antihistamines | Loratadine, Fexofenadine | Management of allergic rhinitis, anaphylaxis |
| Expectorants | Guaifenesin | Loosening and clearance of mucus |
| Antitussives | Codeine, Dextromethorphan | Suppressing persistent cough |
| Decongestants | Fluticasone, Triamcinolone | Reducing nasal congestion |
Use of Respiratory Medications
Respiratory medications are essential in controlling airway inflammation, alleviating bronchospasm, and improving ventilation. In emergency situations, adrenergic agents may be administered to stimulate cardiac output and rapidly dilate airways, enhancing oxygenation.
Types of Bronchodilators
Antihistamines
These medications block histamine activity, constrict smooth muscle in nasal passages, decrease secretions, and reduce capillary permeability. They are highly effective in allergic rhinitis and anaphylaxis.
Decongestants
Decongestants may be adrenergic, anticholinergic, or corticosteroid-based. They shrink swollen nasal tissues, improving airflow and easing congestion.
Antitussives
These agents suppress cough by acting on the brain’s cough center, reducing the urge to cough.
Expectorants
Expectorants help thin mucus, making it easier to expel from the respiratory tract.
Short-Acting Beta-Adrenergic Agonists (SABA)
SABAs, such as albuterol, are essential in acute asthma management, providing rapid relief by relaxing bronchial smooth muscle. For example, Valine, a 24-year-old nursing student with newly diagnosed asthma, experiences post-exertional shortness of breath and chest tightness; in such cases, an inhaled SABA offers quick symptom relief.
Long-Acting Beta2 Agonists (LABA)
LABAs, including salmeterol and formoterol, are intended for long-term symptom control in asthma and COPD, not for acute episodes. They are commonly combined with inhaled corticosteroids and typically administered twice daily.
Anticholinergics
Ipratropium is the most commonly used anticholinergic bronchodilator. By blocking acetylcholine in airway smooth muscle, it prevents bronchoconstriction and facilitates airflow, particularly in COPD, chronic bronchitis, and emphysema.
Contraindications for Ipratropium:
| Condition | Reason for Avoidance |
|---|---|
| Glaucoma | May worsen intraocular pressure |
| Enlarged prostate | Can aggravate urinary retention |
| Urinary retention disorders | May exacerbate symptoms |
Adverse Effects: Cough, nervousness, nausea, xerostomia, headache, and, rarely, paradoxical bronchospasm or anaphylaxis.
Drug Interactions with Ipratropium
Only one direct drug contraindication exists—revefenacin. Caution is required when combined with other anticholinergics or drugs metabolized by the CYP450 system.
| Condition | Potential Interacting Medications |
|---|---|
| Depression, anxiety | Antidepressants, anxiolytics |
| Seasonal allergies | Antihistamines |
| Parkinson’s disease | Anticholinergics |
| Gastrointestinal issues | Antacids, GI medications |
| Overactive bladder | Anticholinergics |
| Use of other bronchodilators | Additional respiratory agents |
Dosage Information for Ipratropium
| Parameter | Details |
|---|---|
| Typical dosage | 0.25–0.5 mg per 2.5 mL |
| Renal/Hepatic adjustment | Not required |
| Use in asthma | For exacerbations only, not as rescue therapy |
| Compatibility | Can be nebulized with albuterol or levalbuterol within 1 hour of mixing |
NR 293 Edapt
Key Patient Education Points:
- Not for individuals under 12 years old (Atrovent HFA not for under 18).
- Not a rescue inhaler; use SABAs for acute attacks.
- Avoid high heat; store at room temperature.
- If using a nebulizer, space doses 6–8 hours apart.
- Avoid eye contact—especially important for patients with glaucoma.
Albuterol: A Beta Agonist
Mechanism of Action: Stimulates beta-2 adrenergic receptors in bronchial smooth muscle, causing relaxation and bronchodilation.
| Body System | Effect |
|---|---|
| Respiratory | Bronchodilation |
| Cardiovascular | Mild vasoconstriction, possible increased heart rate |
Contraindications: Allergy to albuterol, uncontrolled cardiovascular disease.
Adverse Effects: Tachycardia, chest discomfort, dizziness, nervousness, headache.
| Dosage Form | Max Daily Dose (Adults) | Max Daily Dose (Pediatrics) |
|---|---|---|
| Inhalation/Oral | 32 mg | 12 mg |
Patient Education:
- Supervise children during use.
- Administer 15–30 min before exercise to prevent bronchospasm.
- Avoid if allergic to milk proteins (ProAir RespiClick).
Theophylline: Overview
Acts as a CNS stimulant and bronchodilator, metabolizing into caffeine. Increases respiratory rate and enhances cardiac output, but requires careful dosing due to a narrow therapeutic range.
| Therapeutic Range | mcg/mL |
|---|---|
| Standard | 10–20 |
| Preferred by clinicians | 5–15 |
| Toxicity likely | >20 |
Key Caution: Smoking accelerates metabolism, lowering drug levels. Dose adjustments may be needed for smokers or those who recently quit.
Preventive Asthma Medications
Used for long-term control, not acute relief. May include monoclonal antibodies (e.g., omalizumab, mepolizumab) and inhaled corticosteroids (e.g., fluticasone).
| Medication | Action |
|---|---|
| Omalizumab | Binds IgE |
| Mepolizumab | Blocks IL-5 receptor (6+ years) |
| Benralizumab | Blocks IL-5 receptor (12+ years) |
Inhaled Corticosteroids:
- Rinse mouth after use to prevent oral candidiasis.
- Avoid in severe milk protein allergy.
Montelukast (LTRA)
Blocks leukotrienes, reducing airway inflammation. Not for acute asthma attacks.
| Indication | Adult Dose |
|---|---|
| Asthma/Allergic Rhinitis | 10 mg daily |
| Exercise-Induced Bronchospasm | 10 mg at least 2 hrs before exercise |
Monitoring: Check liver enzymes (ALT, AST) during therapy.
Nursing Interventions
| Intervention | Key Details |
|---|---|
| Inhaler technique | Demonstrate and observe patient return-demonstration |
| Dose adherence | Prevent under- or overdosing |
| MDI coordination | Wait 1–2 min between puffs of same drug; 2–5 min between different inhalers |
| Spacer use | Improves delivery efficiency |
Evaluation of Medication Effectiveness
- Clear airway
- Reduced congestion
- Improved oxygenation
- Patient demonstrates understanding and correct self-care techniques
Documentation Guidelines
- Respiratory assessment findings
- Medication response and side effects
- Device use and care plan updates
Antihistamines Overview
Block H1 receptors to reduce allergic responses. Effective for rhinitis, urticaria, and anaphylaxis.
Adverse Effects: Drowsiness, dry mouth, constipation, urinary retention.
Conclusion
A comprehensive understanding of bronchodilators, corticosteroids, LTRAs, and adjunct therapies enables healthcare providers to tailor treatment to each patient’s needs. Effective education, proper inhaler technique, and close monitoring ensure safety and optimize respiratory health.
References
American Thoracic Society. (2021). Guidelines for the management of asthma. https://www.thoracic.org
Dhingra, N. (2020). Pharmacotherapy for respiratory disorders. Journal of Clinical Pharmacy, 45(2), 150–162.
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MedlinePlus. (2022). Antihistamines. https://medlineplus.gov
National Heart, Lung, and Blood Institute. (2023). Asthma medications. https://www.nhlbi.nih.gov
U.S. Food and Drug Administration. (2021). Ipratropium bromide inhalation solution. https://www.fda.gov
U.S. National Library of Medicine. (2022). Albuterol. https://medlineplus.go