Respiratory System Medications

• This module covers upper respiratory infections, influenza, and pharmacological treatments for these conditions.

Respiratory Review

• The respiratory system includes the nasal cavity, pharynx, epiglottis, larynx, trachea, carina, right mainstem bronchus, segmental bronchi, terminal bronchiole, respiratory bronchiole, alveolar duct, alveoli, and Septa Pores of Kohn.
• Goblet cells produce mucus; cilia help move dust and debris.
• The respiratory unit includes bronchioles, alveolar ducts, and alveoli which facilitates high surface area for gas exchange.
• Conducting airways consist of the trachea, bronchi, and bronchioles, spanning from generations 0 to 22.

Case Study: Initial Presentation

• W.F., a 47-year-old male welder, presents with nasal congestion and cough.
• There is a high rate of upper respiratory infections at his workplace.

Upper Respiratory Infections (URIs)

• URIs are infectious diseases in the upper respiratory tract.
• Common URIs include the common cold, laryngitis, pharyngitis, rhinitis, sinusitis, and tonsillitis.

Understanding the Common Cold (Acute Viral Rhinitis)

• Viral infections are the most common cause.
• The virus invades tissues of the upper respiratory tract, causing URI.
• Excessive mucus production results from the inflammatory response.
• Fluid drips from the pharynx into the esophagus and lower respiratory tract, causing symptoms like sore throat, coughing, and upset stomach.
• Irritation of the nasal mucosa triggers the sneeze reflex.
• Mucosal irritation causes the release of inflammatory and vasoactive substances like histamines, which dilate small blood vessels in the nasal sinuses, leading to congestion.

Histamine Reactions

• Mast cells are important activators of the inflammatory response.
• When activated, mast cells release histamine, causing an immune response.
• Histamine is a vasoactive substance, causing constriction of smooth muscle, capillary dilation, and capillary permeability.

Treatment of the Common Cold and URIs

• The combined use of antitussives, expectorants, antihistamines, nasal decongestants, glucocorticoids, and mucolytics may alleviate symptoms.
• Symptomatic treatment does not eliminate the causative pathogen but relieves symptoms only.

Cough Physiology

• Respiratory secretions and foreign objects are naturally removed by the cough reflex.
• The cough reflex induces coughing and expectoration, initiated by irritation of sensory receptors in the respiratory tract.
• Two basic types of cough are productive and nonproductive.
• Productive coughs are congested and remove excessive secretions.
• Nonproductive coughs are dry.

Antitussives

• Antitussives are drugs used to stop or reduce coughing.
• Opioid and non-opioid versions exists.
• They are used only for nonproductive coughs.
• They stop the cough reflex when the cough is nonproductive and/or harmful.

Antitussives: Non-Productive Coughs

• Opioid antitussives include codeine and hydrocodone, which centrally act on the medulla to suppress the cough reflex, but can cause CNS depression, N/V, and constipation.
• They are contraindicated in asthma, head injury, and renal/liver impairment.
• Non-opioid antitussives include dextromethorphan (Robitussin OTC), which suppresses the cough in the medulla.
• Side effects from non-opioid antitussives: dizziness, drowsiness, nausea, and high doses can cause hallucinations.
• Alcohol use is contraindicated with non-opioid antitussives.
• Benzonatate (Tessalon) is also a Non-Opioid antitussive (gel caps) prescription.
• Benzonatate acts peripherally on stretch receptors in the respiratory tract, causing a choking feeling, numbness, dizziness, confusion, and hallucination.

Antitussives: Nursing Implications

• Perform respiratory and cough assessment, and assess for allergies.
• Instruct patients to avoid driving or operating heavy equipment due to sedation, drowsiness, or dizziness.
• Patients taking chewable tablets or lozenges should not drink liquids for 30 to 35 minutes afterward.
• Report symptoms like a cough lasting more than a week, persistent headache, fever, or rash to the caregiver.
• Do not dilute liquid or elixirs.
• Do not chew Tesselon pills.
• Monitor for intended therapeutic effects.

Expectorants: Productive Coughs

• Expectorants aid in the removal of mucus by reducing the viscosity of secretions and disintegrating and thinning them.
• The mechanism of action involves direct stimulation and reflex stimulation.
• The final result is thinner mucus that is easier to remove.
• They are indicated for productive coughs associated with the common cold, bronchitis, laryngitis, pharyngitis, coughs caused by chronic sinusitis, pertussis, influenza, and measles.

Expectorants: Drug Effects

• By loosening and thinning sputum and bronchial secretions, the tendency to cough is indirectly diminished.

Expectorants

• Guaifenesin (Robitussin, Mucinex) is orally administered.
• Direct stimulation is one mechanism of action, where the secretory glands are stimulated directly to increase their production of respiratory tract fluids.
• Reflex stimulation involves the drug causing irritation of the GI tract, leading to loosening and thinning of respiratory tract secretions.
• Administration involves swallowing sustained-release capsules or tablets and increasing fluid intake while taking.
• Side effects may include rash, headache, nausea, and vomiting.

Expectorants: Nursing Interventions

• Patients taking expectorants should receive more fluids to help loosen and liquefy secretions.
• Report symptoms like a fever, cough, or other symptoms lasting longer than a week.
• Read labels for duration or combined other medications.

Antihistamines

• Antihistamines directly compete with histamine for specific receptor sites.
• There are multiple histamine receptors, H₁ and H₂.
• They are used in the management of nasal allergies; seasonal or perennial allergic rhinitis; allergic reactions; motion sickness; Parkinson's disease; and sleep disorders.
• They are also used to relieve symptoms associated with the common cold, such as sneezing and runny nose.
• They offer palliative treatment; however they are not curative.

Antihistamines: Mechanism of Action

• Antihistamines block the action of histamine at H₁ receptor sites, competing with histamine for binding at unoccupied receptors.
• They cannot push histamine off the receptor if already bound.
• The binding of H₁ blockers to the histamine receptors prevents the adverse consequences of histamine stimulation, such as vasodilation, increased GI and respiratory secretions, and increased capillary permeability.

Antihistamines

• H1 Antagonists properties include antihistaminic, anticholinergic and some sedative.
• Examples of first-generation antihistamines (centrally/peripherally) include diphenhydramine (Benadryl) and promethazine (Phenergan).
• First generation antihistamines should be avoided with older patients.
• Examples of second-generation antihistamines (peripherally) include loratadine (Claritin), cetirizine(Zyrtec), fexofenadine (Allegra), and desloratadine (Clarinex).

Histamine vs. Antihistamine Effects

• Histamine causes cardiovascular dilation and increased permeability and stimulates salivary, gastric, lacrimal, and bronchial secretions.
• Histamine is created when mast cells release histamine and other substances that result in allegic reactions.
• Antihistamine reduces dilation of blood vessels and reduces permeability and reduce salivary, gastric, lacrimal and bronchial secretions.
• Antihistamines binds to histamine receptors ,preventing histamine from causing a response

Antihistamines: Other Effects

• Antihistamines reduce capillary permeability, the wheal and flare formation, and itching in the skin, and have a drying effect because the reduce nasal, salivary and lacrimal gland secretions .
• First-generation antihistamines cause drowsiness.
• Second generation antihistamines are non sedating.

Antihistamines: Adverse Effects

• Anticholinergic (drying) being the most common, with dry mouth, difficulty urinating, constipation, and changes in vision.
• Other adverse effects: drowsiness, mild drowsiness to deep sleep, rebound congestion, CNS stimulation, and vasoconstriction.

Antihistamines- Drug Interactions

• Diphenhydramine can cause additive effects when mixed with alcohol, MAOI's(Monamine Oxidase Inhibitors), and other CNS depressants.

Antihistamines: Nursing Implications

• Gather data about the condition or allergic reaction that required treatment, and assess for drug allergies.
• Contraindications may be present in lower respiratory diseases, particularly those masks other underlying eye issues such as pneumonia.
• Increased intraocular pressure, cardiac or renal disease, hypertension, COPD, peptic ulcer disease, BPH, or pregnancy should be considered with antihistamines.
• Patients should report excessive sedation, confusion, or hypotension and to avoid driving or operating heavy machinery.
• Patients should not take the medications with other prescribed or over-the-counter medications without checking with prescriber.
• Antihistamines is best tolerated when taken with meals. If dry mouth occurs, teach patient to perform frequent mouth care, chew gum, or suck on hard candy (preferably sugarless) to ease discomfort.

Nasal Congestion

• Nasal congestion comes from excessive nasal secretions, inflamed, and swollen nasal mucosa.
• Primary causes include allergies and upper respiratory infections (common cold).

Medications Used for Congestion

• Nasal Glucocorticoids like Beclomethasone, Fluticasone and trimcinolone stabilize themembrane, reduce allergic affect (1-2x a day.)
• Nasal Decongestants like Afrin (neo-synephrine) shrink mucous membranes, decrease blood flow to mucosa. Afrin acts immediately, but >3 days can result in severe rebound congestion.
• Oral Decongestants like Sudafed (pseudoephedrine) have a delayed onset when compared to nasal. Sudafed works longer but vasoconsticts and causes CNS stimulation symptoms like nervous, insomnia, palpitations, and dysrhythmia, and should not be used in with caffeine or energy drinks.

Decongestants and Steroids Nursing Implications

• Decongestants might cause hypertension, palpitations, and CNS stimulation -avoid in patients with these conditions
• Patients on medication therapy for hypertension should check with their physician before taking over-the-counter decongestants
• Assess for drug allergies. Patients should avoid caffeine and caffeine-containing products -Report a fever, cough, or other symptoms lasting longer than a week
• Teach patient the proper use of nasal sprays.

Case Study: Subsequent Presentation

• After five days of treatment with over-the-counter medications, W.F. returns to the nurse complaining of fever, muscle aches, and general malaise; more serious diagnosis may be necessary.

SDOH: Over-the counter Costs

• OTC medication varies Antitussives $10-$30, Expectorants 10-$31, Antihistamines $8-$50, $7.50-$30 and transportation to pharmacy.

Influenza (Flu) Overview

• Influenza Pathophysiology:
  • Highly contagious infection of the respiratory tract. -Caused by a myxovirus -Transmitted by airborne droplets and inhalation -Virus frequently mutates allowing it to infect different species (wild birds, pigs, humans) -Frequent mutation reason for annual vaccinations against new strain

Signs and Symptoms of Influenza (Flu):

• Abrupt Onset of Symptoms
• Cough, fever, myalgia's, headache, sore throat
• Physical Exam
• Dyspnea & crackles in lung fields = PROBLEM
• Weakness
• Complications:
• Pneumonia

Diagnosis of Influenza (Flu)

• Testing for Influenza consists of rapid flu nasal swab, and viral cultures done nasopharyngeal.

Treatment for Influenza (Flu)

• Anti-virals: Treat and prevent for Influenza
• Treat Prevent Influenza can be treated by the following:
• Amantadine (Symmetrel) -Rimantadine (Flumadine)
• Influenza A & B currently recommended by theCDC can be treated by the following: -Neuraminidase Inhibitors- prevent virus from budding & for spreading to other cells -Initiate within 2 days of onset of symptoms to minimize symptoms and decrease length of illness -Include -Zanamivir (Relenza)-inhaler- adverse effects Possible Bronchospasm -Oseltamivir (Tamiflu)--capsule, adverse effects G.I. upset

Influenza (Flu) Costs of care

• Tamiflu $120-$250, Relenza ($60-$70. Access to provider for prescription

influenza Medication Notes

• Peramivir (IV)- Approved December 2014--treatment of uncomplicated influenza in persons 18 years and older (CDC Health Update, 2015)
• Adverse Effects: GI upset

Influenza (Flu)Vaccination

• Inactivated Vaccine -injection in 6+ months old-Safe for those that have medical condition and those that are immunocompromised.
• Live attenuated vaccine is recommended again 2023-2024 and should be used by nasal spray, 2-49year olds-only not pregnant, healthy individuals. -Vaccines protect against H1N1 virus, FluMap, history of Guilian Barre dyndrome.

Case Study: Patient Presentation

• A 22-year-old reports relief regarding OTC decongest spray, but symptoms have returned worse in two weeks.

Patient Questions

• Explanation to why the symptoms are worsening symptoms, what the medication is for, OTC other measures to help in the medical situation.

Explore mechanisms of action, side effects, and precautions of respiratory medications. Learn about mucolytics, antihistamines, decongestants, corticosteroids, and expectorants. Understand how these drugs affect mucus viscosity, inflammation, congestion, and related conditions.