The respiratory system is essential for life, facilitating the exchange of oxygen and carbon dioxide between the body and the environment. Conditions affecting the respiratory system, such as asthma, chronic obstructive pulmonary disease (COPD), infections, and allergies, can significantly impair breathing and overall health. Medications targeting the respiratory system are designed to improve airflow, reduce inflammation, manage secretions, and treat underlying causes.

A solid understanding of these medications is critical for safe administration, effective monitoring of patient responses and adverse effects, and providing essential education, particularly regarding the correct use of inhalation devices. This lesson will provide a more detailed overview of key medication classes used to treat respiratory conditions.

1. Bronchodilators: Opening the Airways

Bronchodilators are a class of medications that relax the smooth muscles surrounding the airways, leading to widening (bronchodilation) and improved airflow. They are primarily used to relieve bronchospasm, a sudden constriction of the airways that causes symptoms like wheezing, shortness of breath, and chest tightness.

a. Beta-2 Adrenergic Agonists

These are the most commonly used bronchodilators. They work by stimulating beta-2 adrenergic receptors, which are abundant in the smooth muscle of the bronchioles.

• Mechanism of Action: When beta-2 receptors are stimulated, they activate an enzyme that leads to the relaxation of smooth muscle cells in the airways, causing bronchodilation.

• Types:

  • Short-Acting Beta-2 Agonists (SABAs): (e.g., Salbutamol/Albuterol, Terbutaline)

    • Characteristics: Rapid onset of action (within minutes), relatively short duration (4-6 hours).

    • Uses: Primarily used as “rescue” medications for quick relief of acute bronchospasm during asthma exacerbations or for preventing exercise-induced bronchospasm.

    • Side Effects: Common side effects are related to systemic absorption and stimulation of beta receptors in other areas: tremor (especially in the hands), tachycardia (increased heart rate), palpitations (awareness of heartbeat), nervousness, headache, and sometimes hypokalemia (low potassium).

    • Nursing Implications: Educate patients that SABAs are for quick relief of symptoms and should be carried with them at all times if they have asthma. Instruct on the proper technique for using metered-dose inhalers (MDIs) or nebulizers. Monitor heart rate and assess for tremor after administration. Teach patients that increasing use of a SABA indicates worsening asthma control and they should seek medical attention.

  • Long-Acting Beta-2 Agonists (LABAs): (e.g., Salmeterol, Formoterol, Indacaterol)

    • Characteristics: Slower onset of action than SABAs but a much longer duration (typically 12 hours or more).

    • Uses: Used as maintenance therapy for persistent asthma (always in combination with an inhaled corticosteroid) and for symptomatic relief in COPD. LABAs should never be used alone for the treatment of asthma as this has been associated with an increased risk of severe asthma exacerbations and death. They should only be added if asthma is not well-controlled on an inhaled corticosteroid alone.

    • Side Effects: Similar to SABAs but generally less pronounced due to slower absorption. Headache, tremor, palpitations. Rare but serious risks when used alone in asthma include severe exacerbations.

    • Nursing Implications: Educate patients that LABAs are preventer medications and do not provide quick relief for acute symptoms. Emphasize that for asthma, they must always be used in conjunction with an inhaled corticosteroid in a combination inhaler or as two separate inhalers. Instruct on proper inhaler technique.

b. Anticholinergics

These medications block the action of acetylcholine, a neurotransmitter that can cause bronchoconstriction.

• Mechanism of Action: Acetylcholine acts on muscarinic receptors in the airways, causing smooth muscle contraction and increased mucus secretion. Anticholinergics block these receptors, leading to bronchodilation and reduced mucus production.

• Types:

  • Short-Acting Muscarinic Antagonists (SAMAs): (e.g., Ipratropium bromide)

    • Characteristics: Slower onset than SABAs but can last longer.

    • Uses: Often used in combination with a SABA (e.g., in a nebulized solution like DuoNeb) for acute severe asthma exacerbations. A cornerstone of maintenance therapy for COPD.

    • Side Effects: Primarily local due to inhalation: dry mouth, cough, headache. Less systemic side effects compared to inhaled beta-agonists.

    • Nursing Implications: Instruct on proper inhaler or nebulizer technique. Educate on dry mouth as a common side effect.

  • Long-Acting Muscarinic Antagonists (LAMAs): (e.g., Tiotropium, Aclidinium, Umeclidinium)

    • Characteristics: Long duration of action (typically 24 hours).

    • Uses: Used as maintenance therapy for COPD to improve airflow and reduce exacerbations.

    • Side Effects: Dry mouth is the most common. Less common are constipation, urinary retention, and blurred vision.

    • Nursing Implications: Educate patients that this is a maintenance medication, not for acute relief. Instruct on proper inhaler technique. Monitor for urinary retention, especially in men with prostate issues.

c. Methylxanthines

(e.g., Theophylline, Aminophylline) These are older bronchodilators used less frequently now due to a narrow therapeutic range and potential for significant side effects and drug interactions.

• Mechanism of Action: The exact mechanism is not fully understood but involves bronchodilation and some anti-inflammatory effects.

• Uses: Occasionally used in severe, refractory asthma or COPD, often in oral or intravenous forms.

• Side Effects: Dose-related and can be serious. Common side effects include nausea, vomiting, headache, insomnia, nervousness, and tremors. Signs of toxicity (when blood levels are too high) include persistent vomiting, arrhythmias, and seizures.

• Nursing Implications: Monitor blood levels of theophylline closely to ensure they are within the therapeutic range and avoid toxicity. Monitor for signs and symptoms of toxicity. Be aware of numerous drug interactions that can affect theophylline levels.

2. Anti-Inflammatory Medications: Reducing Airway Swelling

Inflammation is a key component of many chronic respiratory diseases, particularly asthma and COPD. Anti-inflammatory medications are crucial for long-term control and reducing the frequency and severity of exacerbations.

a. Inhaled Corticosteroids (ICS)

These are the most effective anti-inflammatory medications for controlling persistent asthma.

• Mechanism of Action: Corticosteroids reduce inflammation, swelling, and mucus production in the airways. They also make the airways less reactive to triggers like allergens or irritants.

• (e.g., Budesonide, Fluticasone propionate, Fluticasone furoate, Beclomethasone, Mometasone)

  • Uses: The preferred maintenance therapy for all levels of persistent asthma. Also used in moderate to severe COPD to reduce exacerbations.

  • Side Effects: Primarily local side effects due to deposition in the mouth and throat: oral candidiasis (thrush – a fungal infection), hoarseness (dysphonia), and cough. Systemic side effects (adrenal suppression, decreased bone density, slowed growth in children, increased risk of cataracts/glaucoma) are less common at standard inhaled doses but can occur with high doses or prolonged use.

  • Nursing Implications: Educate patients that ICS are preventer medications and do not provide quick relief for acute symptoms. Emphasize the importance of taking them regularly, even when feeling well. Instruct on proper inhaler technique and the critical importance of rinsing the mouth thoroughly with water and spitting it out after each use to minimize the risk of oral thrush. Monitor for signs of oral thrush (white patches in the mouth).

b. Systemic Corticosteroids

(e.g., Prednisone – oral, Methylprednisolone – oral or IV)

• Mechanism of Action: Potent anti-inflammatory and immunosuppressive effects throughout the body.

• Uses: Used for short courses (e.g., 5-7 days) to treat moderate to severe asthma exacerbations or severe COPD exacerbations when inhaled medications are not sufficient. Long-term systemic corticosteroid use is generally avoided due to significant side effects.

• Side Effects: Numerous and can be significant with prolonged use: increased blood glucose (hyperglycemia), increased risk of infection, weight gain, fluid retention, increased appetite, mood changes (irritability, insomnia), osteoporosis, muscle weakness, increased blood pressure, adrenal suppression (requiring gradual tapering of the dose).

• Nursing Implications: Administer as prescribed, often as a short burst or tapered dose. Monitor blood glucose levels, especially in diabetic patients. Monitor for signs of infection. Educate patients on the importance of taking the medication exactly as prescribed and never stopping it abruptly due to the risk of adrenal crisis. Advise on potential side effects.

c. Leukotriene Modifiers

(e.g., Montelukast, Zafirlukast, Zileuton)

• Mechanism of Action: Block the action of leukotrienes, which are inflammatory chemicals released by the body that contribute to bronchoconstriction, mucus production, and airway swelling.

• Uses: Used as maintenance therapy for asthma, prevention of exercise-induced bronchospasm, and for allergic rhinitis. They are generally less potent than inhaled corticosteroids for controlling asthma inflammation.

• Side Effects: Generally well-tolerated. Common side effects include headache, gastrointestinal upset, and liver enzyme elevation (especially with Zileuton). Rare but serious neuropsychiatric events (e.g., mood changes, agitation, depression, suicidal thoughts) have been associated with Montelukast.

• Nursing Implications: Administer as prescribed (often once daily in the evening for Montelukast). Educate patients on potential neuropsychiatric side effects and to report any changes in mood or behavior to their healthcare provider.

d. Mast Cell Stabilizers

(e.g., Cromolyn sodium, Nedocromil) Less commonly used now compared to ICS.

• Mechanism of Action: Prevent the release of inflammatory mediators (like histamine and leukotrienes) from mast cells in the airways.

• Uses: Used as preventer medication for mild persistent asthma, particularly for preventing exercise-induced or allergen-induced asthma. Not for acute relief.

• Side Effects: Generally well-tolerated. Cough and dry mouth are possible.

• Nursing Implications: Educate that this is a preventer medication that needs to be used regularly to be effective.

3. Medications for Clearing Secretions: Helping to Cough Up Mucus

Excessive or thick mucus can obstruct airways and make breathing difficult. These medications help to loosen and clear secretions.

a. Expectorants

(e.g., Guaifenesin)

• Mechanism of Action: Increase the volume and decrease the viscosity (thickness) of respiratory secretions, making them thinner and easier to cough up.

• Uses: Symptomatic relief of cough associated with colds, bronchitis, and other respiratory infections.

• Side Effects: Generally well-tolerated. Nausea, vomiting, and gastrointestinal upset can occur.

• Nursing Implications: Advise patients to drink plenty of fluids (water is best) while taking expectorants, as hydration is crucial for loosening secretions.

b. Mucolytics

(e.g., Acetylcysteine, Dornase alfa)

• Mechanism of Action: Break down the chemical bonds within mucus, making it less thick and sticky. Dornase alfa specifically breaks down DNA in the thick secretions of cystic fibrosis patients.

• Uses: To loosen thick, tenacious secretions in conditions like COPD, cystic fibrosis (Dornase alfa), and sometimes pneumonia. Acetylcysteine is also used as an antidote for acetaminophen overdose.

• Side Effects: Acetylcysteine: Nausea, vomiting, bronchospasm (can occur, especially in patients with reactive airway disease), has a strong sulfur odor. Dornase alfa: Voice changes, pharyngitis, chest pain.

• Nursing Implications: Acetylcysteine is often administered by nebulization or direct instillation into a tracheostomy tube. Monitor for bronchospasm after administration. Dornase alfa is also administered by nebulization.

4. Medications for Respiratory Infections

Infections such as pneumonia, bronchitis, and influenza can significantly impact respiratory function. Treatment depends on the causative pathogen:

• Antibiotics: For bacterial infections (e.g., pneumonia, bacterial bronchitis). The choice depends on the suspected or identified bacteria and local resistance patterns. (Refer to lessons on Antimicrobial Agents).

• Antivirals: For viral infections (e.g., influenza – Oseltamivir/Tamiflu, Zanamivir/Relenza). These are most effective when started early in the illness.

• Antifungals: For fungal infections affecting the lungs (e.g., Aspergillosis, Histoplasmosis). (Refer to lessons on Antimicrobial Agents).

5. Medications for Allergic Rhinitis

Allergic rhinitis (hay fever) is an inflammatory condition of the nasal passages caused by allergens. While primarily affecting the upper respiratory tract, it often coexists with asthma and its treatment can impact overall respiratory health.

• Antihistamines: (e.g., Cetirizine, Loratadine, Fexofenadine – non-sedating; Diphenhydramine, Chlorpheniramine – sedating)

  • Mechanism: Block the action of histamine, reducing itching, sneezing, and rhinorrhea (runny nose).

  • Side Effects: Sedation (more common with older agents), dry mouth, dizziness.

• Intranasal Corticosteroids: (e.g., Fluticasone nasal spray, Budesonide nasal spray, Mometasone nasal spray)

  • Mechanism: Reduce inflammation in the nasal passages. Very effective for controlling nasal allergy symptoms.

  • Side Effects: Nasal irritation, dryness, nosebleeds.

• Decongestants: (e.g., Pseudoephedrine – oral; Oxymetazoline – nasal spray)

  • Mechanism: Cause vasoconstriction in the nasal passages, reducing congestion.

  • Side Effects: Oral: increased heart rate, blood pressure, nervousness, insomnia. Nasal sprays: rebound congestion if used for more than a few days.

  • Nursing Implications: Educate on potential side effects. Advise caution with oral decongestants in patients with hypertension or heart disease. Instruct on proper use of nasal sprays and the risk of rebound congestion with overuse.

Nursing Considerations Across Respiratory Medications

Nurses play a vital role in the care of patients receiving respiratory medications.

• Assessment:

  • Perform thorough respiratory assessments: rate, rhythm, depth, effort of breathing, use of accessory muscles, presence of cough, sputum characteristics, breath sounds (wheezing, crackles), oxygen saturation.

  • Assess the patient’s history of respiratory conditions, allergies, and smoking status.

  • Assess the patient’s understanding of their condition, triggers, and prescribed medications.

  • Assess the patient’s ability to use inhalation devices correctly.

• Administration:

  • Administer medications as prescribed, paying close attention to the correct route (inhaled, oral, IV) and dosage.

  • Crucially, ensure proper technique for inhaled medications. Demonstrate the technique and have the patient return demonstrate. Teach the importance of shaking MDIs, proper positioning, slow inhalation, holding breath, and waiting between puffs. Teach how to use spacers with MDIs to improve delivery and reduce oral deposition.

  • For nebulized medications, ensure proper setup and use of the nebulizer device.

• Monitoring:

  • Monitor for the therapeutic effect of the medication (e.g., improved breathing, reduced wheezing, decreased cough, improved oxygen saturation).

  • Monitor for adverse effects specific to the medication class and individual drug (e.g., tremor/tachycardia with beta-agonists, dry mouth with anticholinergics, oral thrush with ICS, signs of toxicity with theophylline).

  • Monitor vital signs, especially heart rate and respiratory rate.

  • Monitor oxygen saturation using pulse oximetry.

  • Monitor for signs of worsening respiratory status or exacerbation.

  • Monitor for signs of infection if applicable.

• Patient Education:

  • Provide clear and comprehensive education about each prescribed medication: its name, purpose (e.g., rescue vs. preventer), dosage, schedule, and duration.

  • Provide detailed instruction and demonstration on proper inhalation technique.

  • Educate on potential side effects and when to report them to the healthcare provider.

  • Emphasize the importance of adherence to maintenance medications, even when symptoms are controlled.

  • Educate on recognizing signs of worsening symptoms or exacerbation and when to use rescue medication or seek emergency care.

  • Educate on identifying and avoiding respiratory triggers (allergens, irritants, smoke).

  • Strongly encourage and support smoking cessation efforts.

  • Educate on the importance of vaccinations (e.g., influenza, pneumococcal) for preventing respiratory infections.

• Action Plan: For patients with asthma or COPD, educate them on using a written action plan that guides them on adjusting medications based on their symptoms and peak flow readings (if applicable).

• Collaboration: Work closely with physicians, respiratory therapists, pharmacists, and other healthcare professionals to optimize patient care.