NR 293 Edapt

NR 293 Edapt

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Chamberlain University

NR-293: Pharmacology for Nursing Practice

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Date

Week 3: Gas Exchange and Bronchodilators

Introduction to Bronchodilators

Effective gas exchange begins with a careful respiratory assessment, which prioritizes nursing actions accordingly. This discussion will focus on the pharmacotherapeutic interventions associated with respiratory medications, specifically bronchodilators. Each class of respiratory medication can be prioritized based on its administration sequence—first, second, and so forth. These medications facilitate breathing by dilating airways, promoting the clearance of secretions, and reducing inflammation. Some respiratory medications act singularly, while others are combination products that utilize multiple drug actions.

Conditions Treated by Respiratory Medications

Respiratory medications are utilized to address a variety of conditions, including:

• Allergies and hay fever
• Chronic obstructive pulmonary disease (COPD)
• Asthma
• Emphysema
• Chronic bronchitis

Rescue Inhalers and Drug Classifications

The short-acting inhaled beta2-agonists are recommended for use as rescue inhalers rather than for daily maintenance to prevent shortness of breath. The primary classifications of respiratory drugs include bronchodilators, antihistamines, expectorants, antitussives, and decongestants.

Use of Respiratory Medications

Respiratory medications are crucial in managing a variety of disorders, such as allergies, asthma, COPD, emphysema, and chronic bronchitis. In emergencies, adrenergic drugs are used to enhance cardiac output and support effective respiration through bronchodilation.

Types of Bronchodilators

Bronchodilators can be categorized further based on their mechanisms and effects. Subjective and objective symptoms help determine the most suitable medication.

1. Antihistamines: These drugs constrict smooth muscle, reduce body secretions, and increase capillary permeability, making them effective for allergic rhinitis and anaphylaxis.
2. Decongestants: These are categorized into adrenergics, anticholinergics, and topical corticosteroids. They shrink swollen nasal mucous membranes and relieve nasal congestion.
3. Antitussives: These medications suppress the cough reflex by acting on the brain’s cough center.
4. Expectorants: They aid in the expulsion of mucus from the respiratory tract by thinning secretions.

Short-Acting Beta-Adrenergic Agonists (SABA)

Bronchodilators are essential for treating various respiratory conditions characterized by inflammation and bronchoconstriction. Short-acting beta-adrenergic agonists, such as albuterol, are indicated for immediate relief during asthma attacks. These medications work by relaxing and dilating smooth muscle in the bronchi and bronchioles, facilitating airflow and improving oxygenation.

Patient Scenario: Valine

For example, Valine, a 24-year-old nursing student newly diagnosed with asthma, experiences tightness in her chest and difficulty breathing after exertion. In this case, she should use her short-acting inhaled beta2-agonists for relief.

Long-Acting Beta2 Agonists (LABA)

Unlike SABAs, long-acting beta2 agonists are not intended for acute bronchoconstriction. They are prescribed for long-term maintenance therapy in conditions such as asthma and COPD and are typically taken twice daily. Common examples include salmeterol and formoterol, often used in conjunction with inhaled corticosteroids.

Anticholinergics

Ipratropium, the most widely used anticholinergic bronchodilator, is effective for preventing bronchospasm in patients with COPD, bronchitis, and emphysema. It works by blocking acetylcholine to facilitate bronchodilation.

Mechanism of Action

Acetylcholine plays a crucial role in bronchial smooth muscle contraction, which can be detrimental in obstructive lung diseases. Anticholinergic drugs like ipratropium block this neurotransmitter, thereby reducing airway constriction.

Adverse Effects

Common adverse reactions to anticholinergic medications include:

• Cough
• Nervousness
• Nausea
• Dry mouth (xerostomia)
• Headache

Serious reactions can include paradoxical bronchospasm and anaphylaxis.

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Drug Interactions with Ipratropium

Ipratropium is primarily used to treat chronic obstructive pulmonary disease (COPD), but it has some potential drug interactions that require caution. The only drug explicitly contraindicated with ipratropium is revefenacin, another inhaled medication used for COPD management. Certain conditions are associated with medications that can interact with ipratropium, including:

It is essential to avoid using any other anticholinergic medications or those metabolized through the CYP450 system alongside ipratropium to prevent adverse interactions.

Dosage Information

Ipratropium is available as a nebulized solution in a 0.02% concentration, containing 0.5 mg in a 2.5 mL vial. Below is a summary of its typical dosing and special considerations:

Patient Education

Proper education for patients using ipratropium is vital to ensure safe and effective use of the medication. The following points are critical:

The most critical points for patients regarding ipratropium inhalation include avoiding contact with the eyes (especially for those with glaucoma) and seeking medical attention if breathing problems worsen rapidly.

Albuterol: A Beta Agonist

Introduction to Albuterol

Albuterol is a short-acting beta-2 agonist (SABA) that acts as a bronchodilator, used primarily to treat bronchospasm in respiratory conditions like asthma and COPD. It can be administered orally or through inhalation, with inhalation being the preferred method due to faster onset and effectiveness.

Indications for Use

Albuterol is primarily indicated for conditions with reversible obstructive airway issues and is also effective for preventing exercise-induced bronchospasm. Beyond respiratory use, albuterol can be employed in other systems due to its mechanism of action, such as treating hypotension and shock.

Mechanism of Action

Albuterol targets beta-2 adrenergic receptors in the lungs, causing smooth muscle relaxation in the airways, thereby facilitating bronchodilation. It may also affect beta-2 receptors in the cardiovascular and nervous systems, leading to potential side effects.

Contraindications and Adverse Effects
Albuterol is contraindicated in patients with known allergies to the drug and those with cardiovascular conditions such as hypertension or arrhythmias. Common side effects include:

• Chest pain
• Rapid heartbeat
• Dizziness
• Nervousness
• Headaches

Dosing Guidelines for Albuterol

Albuterol is available in both oral and inhaled forms, with inhaled preparations offering quicker absorption and action. The typical maximum dosages are:

Proper technique during inhaler use is crucial to ensure medication effectiveness, and patients should rinse their mouths post-use to prevent dental issues.

Patient Education for Albuterol

Key educational points for albuterol include:

Understanding the pharmacological properties, indications, dosages, and patient education for ipratropium and albuterol is essential for effective treatment of respiratory conditions. Proper management of these medications can significantly enhance patient outcomes and ensure safety during therapy.

Theophylline: An Overview

Mechanism of Action and Drug Effects

Theophylline is primarily used for the prevention of acute asthma attacks and is not recommended as a rescue medication during an active attack. While the exact mechanism by which theophylline operates remains unclear, it is known to enhance cyclic adenosine monophosphate (cAMP) levels and act as an antagonist to adenosine receptors. Adenosine is crucial in cellular metabolism and ATP production, which serves as the energy source for all bodily cells. In simpler terms, theophylline can be likened to caffeine, as it is metabolized into caffeine in the body. Caffeine acts as a central nervous system (CNS) stimulant, particularly in the medulla, leading to an increased respiratory rate. At higher doses, caffeine can also stimulate the cardiovascular system, resulting in enhanced cardiac output by increasing the heart’s strength and rate. Additionally, theophylline can enhance kidney function by raising the glomerular filtration rate (GFR), resulting in a diuretic effect. Thus, one could consider theophylline as similar to an energy drink, where both caffeine and theophylline lead to increased energy levels and respiratory stimulation.

Contraindications

The only absolute contraindication for theophylline use is a known allergy to the medication. Caution is advised for patients with active peptic ulcers, seizure disorders, cardiovascular issues, pulmonary edema, liver impairment, hypothyroidism, sepsis, or shock, as the medications used for these conditions may interact with theophylline. Special care should also be taken when prescribing theophylline to neonates, infants, and the elderly.

Tobacco and Theophylline

One significant substance that affects theophylline levels is tobacco. Smoking alters the concentration of theophylline in the bloodstream, as it induces the metabolism of the drug via the CYP1A2 substrate, leading to a reduced pharmacological effect. Consequently, smokers may require higher doses of theophylline. Conversely, if a non-smoker begins smoking while on theophylline, they may experience a resurgence of asthma symptoms due to the drug’s decreased efficacy.

Adverse Effects

Given that theophylline is metabolized into caffeine, its side effects often resemble those of caffeine as a CNS stimulant. Understanding the relationship between the drug’s mechanism and its side effects helps clarify the expected physiological responses, making it easier to comprehend the medication’s use rather than memorizing isolated lists of drugs and their effects.

Drug Interactions

Theophylline is metabolized through the CYP450 system, making it susceptible to interactions with various medications and substances. Riociguat, a medication for pulmonary hypertension, is directly contraindicated with theophylline. Additionally, the herbal supplement St. John’s wort should be avoided. Changes in smoking habits during theophylline treatment are also discouraged. Notably, theophylline can lower the seizure threshold, requiring careful monitoring in patients taking phenytoin (Dilantin), which also undergoes CYP450 metabolism.

Dosages and Therapeutic Range

Theophylline is available in extended-release tablets ranging from 100 mg to 600 mg and an injectable solution of 80 mg per 15 mL. There are no specific dose adjustments required for patients with liver or kidney impairment. Theophylline has a narrow therapeutic window, and toxicity can arise from both overdose and slow metabolism. Regular laboratory monitoring of serum theophylline levels is essential to prevent toxicity. Acute toxicity may occur rapidly after a single large dose or several large doses, whereas chronic toxicity can develop more gradually, allowing the body some time to adapt. Gastrointestinal symptoms are generally associated with acute toxicity, while seizures and cardiovascular issues are more common in chronic overdose.

Patient Education

Patients should be informed about several important considerations when taking theophylline:

• Report any alcohol use or smoking history to your healthcare provider, especially if you have recently quit smoking.
• Notify your healthcare provider of any high fever lasting 24 hours or longer.
• Pregnant or breastfeeding women should consult their doctors before using theophylline.
• Theophylline should not be used as a rescue treatment during an asthma attack.
• Capsules should be swallowed whole; they should not be crushed or chewed.
• Patients should not take two doses simultaneously.
• Avoid sudden changes in smoking habits without consulting a healthcare provider, as dosage adjustments may be necessary.
• Patients should refrain from hazardous activities until they understand how theophylline affects them.
• Many medications and herbal supplements can affect theophylline levels, so inform your healthcare provider of all substances being taken.

Summary

Theophylline serves as a valuable medication for asthma management by preventing acute attacks, but it requires careful monitoring due to its narrow therapeutic range and potential interactions with other substances, particularly tobacco and specific medications. Understanding its pharmacological effects and mechanisms of action can enhance patient safety and treatment outcomes.

Preventive Medications in Asthma Management

Preventive medications are designed for ongoing management of asthma and should not be relied upon as rescue treatments. It is important to use these medications alongside other asthma therapies rather than as standalone treatments. Maintenance treatment with monoclonal antibody therapies (MAA) is recommended for patients suffering from severe asthma, where the effectiveness of these drugs varies based on the specific receptors they target. Common corticosteroids used for respiratory conditions include prednisone and methylprednisolone.

Non-Bronchodilator Medication Overview

Matching medications to their respective actions provides clarity on their roles in asthma treatment. For instance, Omalizumab selectively binds to immunoglobulin E (IgE), while Mepolizumab and Benralizumab function as interleukin-5 receptor antagonists for patients aged six and twelve years or older, respectively. One major benefit of inhaled corticosteroids over systemic corticosteroids is their localized action, which focuses more directly on the lungs.

Rinsing the Mouth: After using a glucocorticoid inhaler, rinsing the mouth is crucial to prevent oral candidiasis.

Inhaled Corticosteroids

Fluticasone is a commonly used inhaled corticosteroid for asthma prevention in both adults and children. The precise mechanism of fluticasone is not fully understood, but it is known to inhibit multiple inflammatory cytokines. It is contraindicated in patients with severe milk protein allergies. The recommended minimum age for fluticasone administration is two years.

Adverse Effects and Interactions: Common side effects of fluticasone include headache, hoarseness, and potential adrenal suppression. Medications such as desmopressin are contraindicated due to their interaction with fluticasone’s mineralocorticoid effects.

Montelukast and Leukotriene Receptor Antagonists

Montelukast functions as a leukotriene receptor antagonist (LTRA), effectively used for the prevention and treatment of asthma and allergic rhinitis. It is important to note that montelukast is not a rescue medication for acute attacks. LTRAs, such as montelukast, work by inhibiting the action of leukotrienes, which contribute to bronchoconstriction and inflammation.

Dosage Guidelines: Montelukast is available in various forms, including 10 mg non-chewable tablets, 4 mg, and 5 mg chewable tablets, with specific dosages recommended for adults and children.

Monitoring and Patient Education

When transitioning from systemic corticosteroids to inhaled corticosteroids, it is vital to monitor for signs of adrenal insufficiency, including fatigue, nausea, and hypotension. Patients should also be educated on the correct use of inhaled medications and the importance of dental hygiene to prevent complications such as oral thrush.

Key Points for Patient Education:

• Fluticasone is not a rescue medication.
• Rinse the mouth after use to prevent infections.
• Monitor for signs of adrenal insufficiency when switching corticosteroids.

Altered Oxygenation and Physical Activity

Altered oxygenation can be decreased and is often related to pathophysiological changes caused by respiratory diseases. Concurrently, patients may experience decreased physical activity due to disease-induced fatigue and low oxygen saturation levels. Additionally, self-actualization needs may decline because of reduced adherence to medication regimens and the resulting undesirable adverse effects.

Nursing Interventions and Patient Education

Nursing interventions aimed at supporting respiratory disease processes focus primarily on compliance, preventing exacerbations, and educating patients about their drug therapies. Key aspects of these interventions include:

Evaluation of Medication Effectiveness

The evaluation of respiratory medications is crucial in determining their efficacy. Indicators of successful treatment include:

Documentation Guidelines

Thorough documentation is a critical component of patient care. Essential details to record include:

Clinical Scenarios

1. A pediatric client with asthma receives omalizumab, and the guardian inquires about the medication and its prescription. The nurse should explain, “Omalizumab blocks allergic reactions that are common in asthma patients. Your child’s pediatrician prescribed it this morning, and it will be given alongside their other asthma medications.”

2. Before administering montelukast to a client post-surgery experiencing an asthma exacerbation, the nurse should assess for allergies to cellulose and lactose, as these contraindicate the medication.

3. It is crucial to match adverse effects to the appropriate drug classifications. Nursing diagnoses should align with supporting statements to create complete nursing diagnoses.

4. The nurse can assess understanding of respiratory management regimens if the patient demonstrates verbalized understanding of their therapeutic management, clear airway maintenance behaviors, and identification of potential complications.

5. Montelukast use necessitates monitoring of ALT and AST levels during therapy to assess liver function.

6. Goals for asthma treatment should include the absence or reduction of congestion, maintenance of airway patency, and identification of potential complications.

7. If a pediatric patient shows swelling of the tongue after receiving omalizumab, this may indicate a life-threatening side effect requiring immediate intervention.

Antihistamines Overview

Introduction

Antihistamines are drugs that compete with histamine for specific receptor sites, primarily H1 receptors, to alleviate allergy symptoms such as allergic rhinitis, hay fever, hives, itching, runny nose, and sneezing. They are often referred to as histamine antagonists, with common suffixes being -ine.

Considerations

It is essential to note that antihistamines cannot reverse histamine already bound to receptors. Administering these medications prior to exposure to allergens can help mitigate symptoms.

Adverse Effects

Drowsiness is the primary side effect of antihistamines, though non-sedating alternatives are available. Other adverse effects may include dry mouth, vision changes, difficulty urinating, and constipation.

Conclusion

In summary, understanding the pathophysiology of respiratory diseases, the role of antihistamines, and the importance of effective nursing interventions can significantly impact patient outcomes. Proper education and adherence to medication regimens are crucial in managing these conditions effectively.

References

American Thoracic Society. (2021). Guidelines for the Management of Asthma. Retrieved from https://www.thoracic.org

National Institute of Health. (2020). Understanding Allergic Rhinitis. Retrieved from https://www.nih.gov

MedlinePlus. (2022). Antihistamines. Retrieved from https://medlineplus.gov

Dhingra, N. (2020). Pharmacotherapy for respiratory disorders. Journal of Clinical Pharmacy, 45(2), 150-162.

NR 293 Edapt

National Heart, Lung, and Blood Institute. (2023). Asthma medications. Retrieved from NHLBI

U.S. Food and Drug Administration. (2021). Ipratropium Bromide Inhalation Solution. Retrieved from FDA

U.S. National Library of Medicine. (2022). Albuterol. Retrieved from MedlinePlus