Ppt chapter 34

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 34

Drugs Affecting the Upper Respiratory System

Chapter 34

Drugs Affecting the Upper Respiratory System


Physiology Physiology

• The respiratory system is composed of the upper and lower respiratory systems.

• The upper respiratory system is composed of the nose, mouth, pharynx, larynx, trachea, and the bronchial tree.

• Air usually moves into the nasal cavity through the nose.

• Nasal hairs catch and filter foreign substances, and the air is warmed and humidified as it passes by blood vessels close to the surface of the epithelial lining in the nasal passage.

• The walls of the nasal cavity are sensitive to irritation.

• When receptors in these walls are stimulated, a CNS reflex is initiated, and a sneeze results.


Upper Respiratory SystemUpper Respiratory System


Pathophysiology Pathophysiology • The most common conditions that affect the upper

respiratory system can be classified as inflammatory responses.

• Common cold is a viral infection that starts in the upper respiratory tract, sometimes spreading to the lower structures.

• Allergic or seasonal rhinitis occurs when the upper airways respond to a specific allergen.

• Sinusitis occurs when the epithelial lining of the sinus cavities becomes inflamed. It can be caused by bacteria or viruses.

• Pharyngitis is an inflammation or infection of the pharynx.

• Laryngitis is an inflammation of the larynx.

• Influenza is an infection caused by any of several strains of myxoviruses.


Antitussive Drugs Antitussive Drugs

• Antitussives are drugs that suppress the cough reflex.

• Many disorders of the upper and lower respiratory tracts, including the common cold, sinusitis, pharyngitis, and pneumonia, are accompanied by an uncomfortable, nonproductive cough.

• Coughing normally is a protective mechanism that forces foreign irritants out of the respiratory system, opening it for more efficient flow of air.

• Prototype drug: dextromethorphan (Robitussin, PediaCare, Vicks 44, Benylin Pediatric)


Dextromethorphan: Core Drug Knowledge Dextromethorphan: Core Drug Knowledge

• Pharmacotherapeutics

– Chronic nonproductive cough

• Pharmacokinetics

– Administered: oral. Metabolism: liver. Excreted: kidneys.

• Pharmacodynamics

– Directly affects the cough center in the medulla


Dextromethorphan: Core Drug Knowledge (cont.)Dextromethorphan: Core Drug Knowledge (cont.)

• Contraindications and precautions

– Chronic coughs resulting from emphysema and asthma

• Adverse effects

– Nausea, vomiting, drowsiness, dizziness, irritability, and restlessness

• Drug interactions

– MAOIs, fluoxetine, quinidine, and sibutramine


Dextromethorphan: Core Patient Variables Dextromethorphan: Core Patient Variables

• Health status

– Assess for contraindications to therapy.

• Life span and gender

– Pregnancy Category C drug

• Lifestyle, diet, and habits

– Advise not to drive or operate heavy equipment.

• Environment

– Assess the environment where the drug will be given.


Dextromethorphan: Nursing Diagnoses and Outcomes Dextromethorphan: Nursing Diagnoses and Outcomes

• Risk for Injury related to sensory–perceptual alteration from drug-induced drowsiness and sedation

– Desired outcome: The patient will remain free from injury related to sedation and drowsiness.

• Risk for Ineffective Airway Clearance related to suppression of cough reflex

– Desired outcome: The patient will maintain his or her baseline respiratory function.


Dextromethorphan: Planning and InterventionsDextromethorphan: Planning and Interventions

• Maximizing therapeutic effects

– In acute or long-term care settings, administer dextromethorphan at evenly spaced intervals to maintain blood levels of the drug at steady state.

• Minimizing adverse effects

– Ensure that safety precautions are used, such as side rails and ambulation assistance.

– Assess respiratory status and movement of air periodically during drug use.


Dextromethorphan: Teaching, Assessment, and EvaluationDextromethorphan: Teaching, Assessment, and Evaluation

• Patient and family education

– Emphasize that sedation, drowsiness, and impaired orientation can occur.

– Caution patients who are taking certain antidepressants.

• Ongoing assessment and evaluation

– Monitor the effect of dextromethorphan on the patient’s motor control, sedation, and respiratory status.


QuestionQuestion

• Dextromethorphan suppresses cough by inhibition of nerve cells in the trachea.

– A. True

– B. False


AnswerAnswer

• B. False

• Rationale: Dextromethorphan is related chemically to the opiate agonists and can suppress coughing as effectively as narcotics.

• The drug directly affects the cough center in the medulla.


Decongestant Drugs Decongestant Drugs

• Decongestants are drugs taken to decrease nasal congestion related to the common cold, sinusitis, and allergic rhinitis, a condition that is caused by an inflammatory response in the upper respiratory tract.

• Nasal decongestants work by constricting the nasal arterioles, thereby decreasing the swelling of the nasal membrane.

• These drugs can be administered orally or topically.

• When decongestants are taken orally, they are absorbed in the body, thus increasing the chance of adverse effects.

• When used topically, the drug has the same therapeutic effects; however, the potential for adverse effects is diminished.

• Prototype drug: pseudoephedrine


Pseudoephedrine: Core Drug Knowledge Pseudoephedrine: Core Drug Knowledge


– Reduces the volume of nasal mucus and is recommended for the temporary relief of nasal congestion


– Administered: oral. Metabolism: liver. Excreted: kidneys. Onset: 30 minutes.


– Causes vasoconstriction in the nasal mucous membranes


Pseudoephedrine: Core Drug Knowledge (cont.)Pseudoephedrine: Core Drug Knowledge (cont.)


– Caution with pregnancy and lactation

• Adverse effects

– Tension, anxiety, restlessness, tremor, insomnia, and weakness


– MAOIs, guanethidine, methyldopa, or furazolidone


Pseudoephedrine: Core Patient Variables Pseudoephedrine: Core Patient Variables

• Health status

– Assess medical history.




– Assess the use of OTC medication.

• Environment



Pseudoephedrine: Nursing Diagnoses and Outcomes Pseudoephedrine: Nursing Diagnoses and Outcomes

• Risk for Injury caused by visual sensory–perceptual alterations (hallucinations) related to drug-induced CNS effects

– Desired outcome: The patient will be protected from injury related to drug use and will demonstrate safety procedures to use if these effects occur.

• Ineffective Tissue Perfusion: Cerebral or Cardiopulmonary related to sympathomimetic effects

– Desired outcome: The patient will be monitored and dosage adjusted to minimize potential perfusion deficits or CNS effects.


Pseudoephedrine: Planning and InterventionsPseudoephedrine: Planning and Interventions


– Encourage patients to use a humidifier, drink plenty of fluids, and avoid smoke-filled rooms.


– Provide the patient with appropriate safety measures.


Pseudoephedrine: Teaching, Assessment, and EvaluationPseudoephedrine: Teaching, Assessment, and Evaluation


– Explain to patients that the purpose of the drug is to promote breathing and relieve congestion.

– Caution patients to avoid using other OTC drugs.


– Monitor patients receiving pseudoephedrine for rebound congestion, sedation, dizziness, weakness, tremor, and urinary retention.


QuestionQuestion

• Pseudoephedrine mimics the actions of the parasympathetic nervous system.

– A. True

– B. False


AnswerAnswer

• B. False

• Rationale: Pseudoephedrine mimics the actions of the sympathetic nervous system and achieves its nasal decongestant effects by causing vasoconstriction in the nasal mucous membranes.


Antihistamines Antihistamines

• Antihistamines are used to relieve symptoms of allergies.

• These drugs block the action of histamine as it is released during the inflammatory response to an antigen.

• Effective for allergic rhinitis.

• Their action restores normal airflow through the upper respiratory system.

• Prototype drug: fexofenadine (Allegra)


Fexofenadine: Core Drug Knowledge Fexofenadine: Core Drug Knowledge


– Relieves symptoms associated with seasonal and perennial allergies


– Administered: oral. Metabolism: liver. Excreted: urine and feces. Peak: 2 to 6 hours.


– Selectively blocks the effects of histamine at H1-receptor sites


Fexofenadine: Core Drug Knowledge (cont.)Fexofenadine: Core Drug Knowledge (cont.)


– Hypersensitivity

• Adverse effects

– Nausea, vomiting, dysmenorrhea, drowsiness, dyspepsia, and fatigue


– Only a few drug interactions are associated with fexofenadine.


Fexofenadine: Core Patient Variables Fexofenadine: Core Patient Variables

• Health status

– Assess pregnancy, lactation, and renal status.




– Evaluate how often the patient drinks apple, grapefruit, or orange juice.

• Environment



Fexofenadine: Nursing Diagnoses and Outcomes Fexofenadine: Nursing Diagnoses and Outcomes

• Risk for Injury caused by drowsiness and fatigue related to drug-induced CNS effects

– Desired outcome: Safety precautions will prevent injury related to drug-induced CNS effects.


Fexofenadine: Planning and InterventionsFexofenadine: Planning and Interventions


– Institute measures to prevent dangers associated with thickening of respiratory secretions.


– Refrain from giving the patient apple, grapefruit, or orange juice with fexofenadine because these juices decrease its absorption.


Fexofenadine: Teaching, Assessment, and EvaluationFexofenadine: Teaching, Assessment, and Evaluation


– Caution patients to take the drug as prescribed.

– Tell patients to avoid the use of other OTC drugs.

– Teach patients to take fexofenadine with a glass of water.


– After several days of taking the fexofenadine, the patient should experience little discomfort associated with the drug’s adverse effects.


QuestionQuestion

• The mechanism of action of fexofenadine is

– A. Selectively blocking histamine at H1-receptor sites

– B. Selectively blocking histamine at H2-receptor sites

– C. Competitively blocking histamine at H1-receptor sites

– D. Competitively blocking histamine at H2-receptor sites


AnswerAnswer

• A. Selectively blocking histamine at H1-receptor sites

• Rationale: Fexofenadine selectively blocks the effects of histamine at H1-receptor sites, decreasing the allergic response.


Expectorant Drugs Expectorant Drugs

• Expectorants are drugs that liquefy lower respiratory tract secretions.

• This effect decreases the viscosity of the secretions and improves airflow.

• Expectorants are available in many OTC preparations.

• Prototype drug: guaifenesin (Robitussin)


Guaifenesin: Core Drug Knowledge Guaifenesin: Core Drug Knowledge


– Relieves dry, nonproductive cough


– Administered: oral. Onset: 30 minutes. Duration: 4 to 6 hours.


– Enhances the output of respiratory tract fluids by reducing the adhesiveness and surface tension of the fluids


Guaifenesin: Core Drug Knowledge (cont.)Guaifenesin: Core Drug Knowledge (cont.)


– Known allergy to medication

• Adverse effects

– GI symptoms, headache, and dizziness


– Guaifenesin has no important drug–drug interactions.


Guaifenesin: Core Patient Variables Guaifenesin: Core Patient Variables

• Health status

– Assess the patient for any past hypersensitivity.




– Assess smoking and alcohol use.


Guaifenesin: Nursing Diagnoses and Outcomes Guaifenesin: Nursing Diagnoses and Outcomes

• Imbalanced Nutrition: Less than Body Requirements related to GI symptoms of nausea and vomiting

– Desired outcome: The patient will maintain baseline weight and nutritional status.

• Ineffective Airway Clearance related to increased viscosity of secretions

– Desired outcome: The patient will demonstrate effective coughing technique and make use of several methods to increase airway clearance.


Guaifenesin: Planning and InterventionsGuaifenesin: Planning and Interventions


– Teach the patient about good pulmonary hygiene, which includes coughing, using deep breathing, drinking plenty of fluids, and using a humidifier.


– Suggest that the patient eats small, frequent meals to alleviate GI upset.


Guaifenesin: Teaching, Assessment, and EvaluationGuaifenesin: Teaching, Assessment, and Evaluation


– Explain to patients that guaifenesin will help make it easier to cough up secretions from the lungs.

– Tell patients not to use guaifenesin for longer than one week.


– Monitor the patient’s reaction to guaifenesin carefully.


QuestionQuestion

• Guaifenesin should only be used for how long?

– A. 3 days

– B. 1 week

– C. 2 weeks

– D. 4 or more weeks


AnswerAnswer

• B. 1 week

• Rationale: Guaifenesin should not be used for longer than one week.

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