1. Antihistamines, Decongestants, Antitussives, and Expectorants
Chapter 36
Antihistamines, Decongestants, Antitussives, and Expectorants
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2. Understanding the Common Cold
Most caused by viral infection (rhinovirus or influenza virus)
Virus invades tissues (mucosa) of upper respiratory tract, causing upper respiratory infection (URI)
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3. Understanding the Common Cold (Cont.)
Excessive mucus production results from the inflammatory response to this invasion.
Fluid drips down the pharynx into the esophagus and lower respiratory tract, causing cold symptoms: sore throat, coughing, upset stomach.
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4. Understanding the Common Cold (Cont.)
Irritation of nasal mucosa often triggers the sneeze reflex.
Mucosal irritation also causes release of several inflammatory and vasoactive substances, dilating small blood vessels in the nasal sinuses and causing nasal congestion.
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5. Treatment of the Common Cold
Involves combined use of antihistamines, nasal decongestants, antitussives, and expectorants
Treatment is symptomatic only, not curative
Symptomatic treatment does not eliminate the causative pathogen.
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6. Treatment of the Common Cold (Cont.)
Difficult to identify whether cause is viral or bacterial
Treatment is “empiric therapy,” treating the most likely cause
Antivirals and antibiotics may be used, but a definite viral or bacterial cause may not be easily identified
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Pediatric Concerns
In 2008, the U.S. Food and Drug Administration (FDA) issued recommendations that over-the-counter (OTC) cough and cold products not be given to children younger than 2 years of age.
Oversedation, seizures, tachycardia, and even death in toddlers
Evidence that such medications are simply not effective in small children
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8. Pediatric Concerns (Cont.)
Parents are advised to consult their children’s pediatricians on the best ways to manage these illnesses.
A 2010 study showed a dramatic decrease in young children’s emergency department visits since the 2008 FDA recommendation.
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9. Audience Response System Question
The common cold is treated with empiric therapy, which means
the medications cure the cold.
the medications only treat the symptoms.
herbal medications are useful to eliminate symptoms.
it is prevented with careful use of medications.
Correct answer: B
Rationale: There is no cure for the common cold, and the efficacy of herbal products is not proven. Treatment rendered can only treat the presenting clinical symptoms.
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10. Supplements and Herbal Products
Vitamin C
Echinacea
Goldenseal
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Antihistamines
Drugs that directly compete with histamine for specific receptor sites
Two histamine receptors
H1 (histamine 1)
H2 (histamine 2)
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12. Anaphylaxis: Severe Allergic Reactions
Release of excessive amounts of histamine can lead to:
Constriction of smooth muscle, especially in the stomach and lungs
Increase in body secretions
Vasodilatation and increased capillary permeability, movement of fluid out of the blood vessels and into the tissues, and drop in blood pressure and edema
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Histamine
Major inflammatory mediator in many allergic disorders
Allergic rhinitis (e.g., hay fever and mold, dust allergies)
Anaphylaxis
Angioedema
Drug fevers
Insect bite reactions
Urticaria (itching)
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14. Antihistamines and Histamine Antagonists
H1 antagonists (also called H1 blockers)
Examples: chlorpheniramine, fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec), diphenhydramine (Benadryl)
Antihistamines have several properties
Antihistaminic
Anticholinergic
Sedative
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15. Antihistamines (Cont.)
H2 blockers or H2 antagonists
Used to reduce gastric acid in peptic ulcer disease
Examples: cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), nizatidine (Axid)
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16. Antihistamines: Mechanism of Action
Block action of histamine at H1 receptor sites
Compete with histamine for binding at unoccupied receptors
Cannot push histamine off the receptor if already bound
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17. Antihistamines: Mechanism of Action (Cont.)
The binding of H1 blockers to the histamine receptors prevents the adverse consequences of histamine stimulation
Vasodilation
Increased gastrointestinal (GI) and respiratory secretions
Increased capillary permeability
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18. Antihistamines: Mechanism of Action (Cont.)
More effective in preventing the actions of histamine rather than reversing them
Should be given early in treatment before all the histamine binds to the receptors
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19. Histamine vs. Antihistamine Effects
Cardiovascular (small blood vessels)
Histamine effects: dilation and increased permeability (allowing substances to leak into tissues)
Antihistamine effects
Reduce dilation of blood vessels
Reduce increased permeability of blood vessels
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20. Histamine vs. Antihistamine Effects (Cont.)
Smooth muscle (on exocrine glands)
Histamine effects: stimulate salivary, gastric, lacrimal, and bronchial secretions
Antihistamine effects: reduce salivary, gastric, lacrimal, and bronchial secretions
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21. Histamine vs. Antihistamine Effects (Cont.)
Immune system (release of substances commonly associated with allergic reactions)
Histamine effects: mast cells release histamine and other substances, resulting in allergic reactions
Antihistamine effects: bind to histamine receptors, thus preventing histamine from causing a response
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22. Antihistamines: Other Effects
Skin: reduce capillary permeability, wheal-and-flare formation, itching
Anticholinergic: drying effect that reduces nasal, salivary, and lacrimal gland secretions (runny nose, tearing, and itching eyes)
Sedative: some antihistamines cause drowsiness
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23. Antihistamines: Indications
Management of:
Nasal allergies
Seasonal or perennial allergic rhinitis (hay fever)
Allergic reactions
Motion sickness
Parkinson’s disease
Sleep disorders
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24. Antihistamines: Indications (Cont.)
Also used to relieve symptoms associated with the common cold
Sneezing, runny nose
Palliative treatment; not curative
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25. Antihistamines: Contraindications
Known drug allergy
Narrow-angle glaucoma
Cardiac disease, hypertension
Kidney disease
Bronchial asthma, chronic obstructive pulmonary disease (COPD)
Sole drug therapy during acute asthmatic attacks
Albuterol or epinephrine
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26. Antihistamines: Contraindications (Cont.)
Peptic ulcer disease
Seizure disorders
Benign prostatic hyperplasia (BPH)
Pregnancy
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27. Antihistamines: Adverse Effects
Anticholinergic (drying) effects: most common
Dry mouth
Difficulty urinating
Constipation
Changes in vision
Drowsiness
Mild drowsiness to deep sleep
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28. Audience Response System Question
Before administering an antihistamine to a patient, it is most important for the nurse to assess the patient for a history of which condition?
Chronic urticaria
Motion sickness
Urinary retention
Insomnia
Correct answer: C
Rationale: The anticholinergic effects of antihistamines may cause difficulty urinating. The other answers are potential indications for an antihistamine.
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29. Antihistamines: Two Types
Traditional: brompheniramine, chlorpheniramine, dimenhydrinate, diphenhydramine, meclizine, and promethazine
Nonsedating: loratadine, cetirizine, and fexofenadine
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30. Nonsedating/Peripherally Acting Antihistamines
Developed to eliminate unwanted adverse effects, mainly sedation
Work peripherally to block the actions of histamine; thus, fewer central nervous system (CNS) adverse effects
Longer duration of action (increases compliance)
Examples: fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec)
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31. Traditional Antihistamines
Older
Work both peripherally and centrally
Have anticholinergic effects, making them more effective than nonsedating drugs in some cases
Examples: diphenhydramine, brompheniramine, chlorpheniramine, dimenhydrinate, meclizine, promethazine
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32. Antihistamines: Nursing Implications
Gather data about the condition or allergic reaction that required treatment; also assess for drug allergies.
Contraindicated in the presence of acute asthma attacks and lower respiratory diseases, such as pneumonia
Use with caution in patients with increased intraocular pressure, cardiac or renal disease, hypertension, asthma, COPD, peptic ulcer disease, BPH, or pregnancy.
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33. Antihistamines: Nursing Implications (Cont.)
Instruct patients to report excessive sedation, confusion, or hypotension.
Instruct patients to avoid driving or operating heavy machinery; advise against consuming alcohol or other CNS depressants.
Instruct patients not to take these medications with other prescribed or OTC medications without checking with their prescribers.
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34. Antihistamines: Nursing Implications (Cont.)
Best tolerated when taken with meals; reduces GI upset
If dry mouth occurs, teach patients to perform frequent mouth care, chew gum, or suck on hard candy (preferably sugarless) to ease discomfort.
Monitor for intended therapeutic effects.
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Nasal Congestion
Excessive nasal secretions
Inflamed and swollen nasal mucosa
Primary causes
Allergies
URIs (common cold)
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Decongestants: Types
Three main types are used:
Adrenergics
Largest group
Sympathomimetics
Anticholinergics
Less commonly used
Parasympatholytics
Corticosteroids
Topical, intranasal steroids
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37. Decongestants: Types (Cont.)
Two dosage forms
Oral
Inhaled or topically applied to the nasal membranes
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Oral Decongestants
Prolonged decongestant effects but delayed onset
Effect less potent than topical
No rebound congestion
Exclusively adrenergics
Example: pseudoephedrine (Sudafed)
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39. Topical Nasal Decongestants
Topical adrenergics
Prompt onset
Potent
Sustained use over several days causes rebound congestion, making the condition worse.
Ephedrine, oxymetazoline, phenylephrine, and tetrahydrozoline
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40. Inhaled Intranasal Steroids and Anticholinergic Drugs
Not associated with rebound congestion
Often used prophylactically to prevent nasal congestion in patients with chronic upper respiratory tract symptoms
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41. Topical Nasal Decongestants (Cont.)
Adrenergics
ephedrine, oxymetazoline
Intranasal steroids
beclomethasone dipropionate (Beconase), budesonide (Rhinocort), flunisolide (Nasalide), fluticasone (Flonase), triamcinolone (Nasacort), ciclesonide (Omnaris)
Intranasal anticholinergic
ipratropium (Atrovent)
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42. Nasal Decongestants: Mechanism of Action
Site of action: blood vessels surrounding nasal sinuses
Adrenergics
Constrict small blood vessels that supply upper respiratory tract structures
As a result, these tissues shrink, and nasal secretions in the swollen mucous membranes are better able to drain.
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43. Nasal Decongestants: Mechanism of Action (Cont.)
Nasal steroids
Antiinflammatory effect
Work to turn off the immune system cells involved in the inflammatory response
Decreased inflammation results in decreased congestion.
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44. Nasal Decongestants: Drug Effects
Shrink engorged nasal mucous membranes
Relieve nasal stuffiness
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45. Nasal Decongestants: Indications
Relief of nasal congestion associated with:
Acute or chronic rhinitis
Common cold
Sinusitis
Hay fever
Other allergies
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46. Nasal Decongestants: Indications (Cont.)
May also be used to reduce swelling of the nasal passage and facilitate visualization of the nasal or pharyngeal membranes before surgery or diagnostic procedures
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47. Nasal Decongestants: Contraindications
Drug allergy
Narrow-angle glaucoma
Uncontrolled cardiovascular disease, hypertension
Diabetes and hyperthyroidism
Inability to close the eyes
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48. Nasal Decongestants: Contraindications (Cont.)
History of cerebrovascular accident or transient ischemic attacks
Long-standing asthma
BPH
Diabetes
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49. Nasal Decongestants: Adverse Effects
Adrenergics Steroids
Nervousness Local mucosal dryness
Insomnia and irritation
Palpitations
Tremors
(Systemic effects caused by adrenergic stimulation
of the heart, blood vessels, and CNS)
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50. Nasal Decongestants: Interactions
Systemic sympathomimetic drugs and sympathomimetic nasal decongestants are likely to cause drug toxicity when given together.
Monoamine oxidase inhibitors and sympathomimetic nasal decongestants raise blood pressure.
Methyldopa
Urinary acidifiers and alkalinizers
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51. Nasal Decongestants: Nursing Implications (Cont.)
Patients should avoid caffeine and caffeine-containing products.
Patients should report a fever, cough, or other symptoms lasting longer than 1 week.
Monitor for intended therapeutic effects.
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52. Audience Response Question
Before administering an adrenergic decongestant, it is most important for the nurse to asses the patient for a history of
cataracts.
gastric ulcer.
diabetes mellitus.
hypothyroidism.
Correct answer: C
Rationale: Adrenergic drugs are contraindicated in patients with narrow-angle glaucoma, uncontrolled cardiovascular disease, hypertension, diabetes, and hyperthyroidism. They are also contraindicated when the patient is unable to close his or her eyes (e.g., after a cerebrovascular accident), as well as in patients with a history of cerebrovascular accident or transient ischemic attacks, long-standing asthma, BPH, or diabetes.
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53. Copyright © 2017, Elsevier Inc. All rights reserved.
Cough Physiology
Respiratory secretions and foreign objects are naturally removed by the cough reflex.
Induces coughing and expectoration
Initiated by irritation of sensory receptors in the respiratory tract
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54. Two Basic Types of Cough
Productive cough: congested; removes excessive secretions
Nonproductive cough: dry cough
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55. Copyright © 2017, Elsevier Inc. All rights reserved.
Coughing
Most of the time, coughing is beneficial.
Removes excessive secretions
Removes potentially harmful foreign substances
In some situations, coughing can be harmful, such as after hernia repair surgery.
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56. Copyright © 2017, Elsevier Inc. All rights reserved.
Antitussives
Drugs used to stop or reduce coughing
Opioid and nonopioid
Used only for nonproductive coughs!
May be used in cases when coughing is harmful
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57. Antitussives: Mechanism of Action
Opioids
Suppress the cough reflex by direct action on the cough center in the medulla
Analgesia, drying effect on the mucosa of the respiratory tract, increased viscosity of respiratory secretions, reduction of runny nose and postnasal drip
Examples
Codeine
Hydrocodone
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58. Antitussives: Mechanism of Action (Cont.)
Nonopioids
Dextromethorphan: works in the same way
Not an opioid
No analgesic properties
No CNS depression
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59. Antitussives: Mechanism of Action (Cont.)
Nonopioids (Cont.)
Benzonatate
Suppress the cough reflex by numbing the stretch receptors in the respiratory tract and prevent reflex stimulation of the medullary cough center
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60. Antitussives: Indications
Used to stop the cough reflex when the cough is nonproductive or harmful
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61. Antitussives: Contraindications
Drug allergy
Opioid dependency
Respiratory depression
Others
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62. Antitussives: Adverse Effects
Benzonatate
Dizziness, headache, sedation, nausea, and others
Dextromethorphan
Dizziness, drowsiness, nausea
Opioids
Sedation, nausea, vomiting, lightheadedness, constipation
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63. Antitussives: Nursing Implications
Perform respiratory and cough assessment and assess for allergies.
Instruct patients to avoid driving or operating heavy equipment because of possible sedation, drowsiness, or dizziness.
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64. Antitussives: Nursing Implications (Cont.)
Report any of the following symptoms to the caregiver:
Cough that lasts more than 1 week
Persistent headache
Fever
Rash
Antitussive drugs are for nonproductive coughs.
Monitor for intended therapeutic effects.
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65. Audience Response System Question
A 94-year-old patient has a severe dry cough. He has coughed so hard that the muscles in his chest are hurting. He is unsteady on his feet and slightly confused. Which drug would be the best choice for this patient’s cough?
Benzonatate (Tessalon Perles) capsules
Dextromethorphan (Robitussin-DM) oral solution
Codeine cough syrup
Guaifenesin (Mucinex)
Correct answer: B
Rationale: Dextromethorphan does not cause respiratory or CNS depression, and it is not an opioid. Guaifenesin is an expectorant that is used to thin excessive mucus, which this patient does not have.
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66. Copyright © 2017, Elsevier Inc. All rights reserved.
Expectorants
Drugs that aid in the expectoration (removal) of mucus
Reduce the viscosity of secretions
Disintegrate and thin secretions
Example: guaifenesin
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67. Expectorants: Mechanisms of Action
Reflex stimulation
Drug causes irritation of the GI tract
Loosening and thinning of respiratory tract secretions occur in response to this irritation
Direct stimulation
The secretory glands are stimulated directly to increase their production of respiratory tract fluids.
Final result: thinner mucus that is easier to remove
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68. Expectorants: Drug Effects
By loosening and thinning sputum and bronchial secretions, the tendency to cough is indirectly diminished.
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69. Expectorants: Indications
Used for the relief of productive coughs associated with:
Common cold
Bronchitis
Laryngitis
Pharyngitis
Coughs caused by chronic paranasal sinusitis
Pertussis
Influenza
Measles
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70. Expectorants: Nursing Implications
Expectorants should be used with caution in older adults and patients with asthma or respiratory insufficiency.
Patients taking expectorants should receive more fluids, if permitted, to help loosen and liquefy secretions.
Report a fever, cough, or other symptoms lasting longer than 1 week.
Monitor for intended therapeutic effects.
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71. Herbal Products: Echinacea
Reduces symptoms of the common cold and recovery time
Adverse effects
Dermatitis
GI disturbance
Dizziness
Headache
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72. Audience Response System Question
A patient with a tracheostomy developed pneumonia. It is very difficult for the patient to cough up the thick, dry secretions he has developed. The nurse identifies which drug as being most effective in helping this patient?
Benzonatate (Tessalon Perles) capsules
Dextromethorphan (Robitussin-DM) oral solution
Codeine cough syrup
Guaifenesin (Mucinex)
Correct answer: D
Rationale: Expectorants such as guaifenesin aid in the expectoration (i.e., coughing up and spitting out) of excessive mucus that has accumulated in the respiratory tract by breaking down and thinning out the secretions.
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