Antihistamines, Decongestants, Antitussives, and Expectorants Chapter 36 Antihistamines, Decongestants, Antitussives, and Expectorants Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Understanding the Common Cold (cont’d) 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Understanding the Common Cold (cont’d) 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Treatment of the Common Cold (cont’d) 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response 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. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Antihistamines Drugs that directly compete with histamine for specific receptor sites Two histamine receptors H1 (histamine1) H2 (histamine2) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines (cont’d) H1 antagonists are commonly referred to as antihistamines Examples: chlorpheniramine, fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec),diphenhydramine (Benadryl) Antihistamines have several properties Antihistaminic Anticholinergic Sedative Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines (cont’d) H2 blockers or H2 antagonists Used to reduce gastric acid in peptic ulcer disease Examples: cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), nizatidine (Axid) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Mechanism of Action (cont’d) The binding of H1 blockers to the histamine receptors prevents the adverse consequences of histamine stimulation Vasodilation Increased GI and respiratory secretions Increased capillary permeability Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Mechanism of Action (cont’d) 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Histamine vs. Antihistamine Effects (cont’d) Smooth muscle (on exocrine glands) Histamine effects Stimulate salivary, gastric, lacrimal, and bronchial secretions Antihistamine effects Reduce salivary, gastric, lacrimal, and bronchial secretions Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Histamine vs. Antihistamine Effects (cont’d) 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 Binds to histamine receptors, thus preventing histamine from causing a response Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Indications Management of: Nasal allergies Seasonal or perennial allergic rhinitis (hay fever) Allergic reactions Motion sickness Parkinson’s disease Sleep disorders Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Indications (cont’d) Also used to relieve symptoms associated with the common cold Sneezing, runny nose Palliative treatment, not curative Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Adverse Effects Anticholinergic (drying) effects, most common Dry mouth Difficulty urinating Constipation Changes in vision Drowsiness Mild drowsiness to deep sleep Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question Prior to 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. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Antihistamines: Two Types Traditional Nonsedating Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nonsedating/Peripherally Acting Antihistamines Developed to eliminate unwanted adverse effects, mainly sedation Work peripherally to block the actions of histamine; thus, fewer CNS adverse effects Longer duration of action (increases compliance) Examples: fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 increased intraocular pressure, cardiac or renal disease, hypertension, asthma, COPD, peptic ulcer disease, BPH, or pregnancy Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Nursing Implications (cont’d) 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 over-the-counter medications without checking with prescriber Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antihistamines: Nursing Implications (cont’d) Best tolerated when taken with meals—reduces GI upset If dry mouth occurs, teach patient to perform frequent mouth care, chew gum, or suck on hard candy (preferably sugarless) to ease discomfort Monitor for intended therapeutic effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Nasal Congestion Excessive nasal secretions Inflamed and swollen nasal mucosa Primary causes Allergies Upper respiratory infections (common cold) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Decongestants: Types Three main types are used Adrenergics Largest group Sympathomimetics Anticholinergics Less commonly used Parasympatholytics Corticosteroids Topical, intranasal steroids Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Decongestants: Types (cont’d) Two dosage forms Oral Inhaled/topically applied to the nasal membranes Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Oral Decongestants Prolonged decongestant effects, but delayed onset Effect less potent than topical No rebound congestion Exclusively adrenergics Example: pseudoephedrine (Sudafed) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Topical Nasal Decongestants Topical adrenergics Prompt onset Potent Sustained use over several days causes rebound congestion, making the condition worse Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Topical Nasal Decongestants (cont’d) Adrenergics phenylephrine (Neo-Synephrine) Intranasal steroids beclomethasone dipropionate (Beconase), budesonide (Rhinocort), flunisolide (Nasalide), fluticasone (Flonase), triamcinolone (Nasacort), ciclesonide (Omnaris) Intranasal anticholinergic ipratropium (Atrovent) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Mechanism of Action (cont’d) Nasal steroids Antiinflammatory effect Work to turn off the immune system cells involved in the inflammatory response Decreased inflammation results in decreased congestion Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Drug Effects Shrink engorged nasal mucous membranes Relieve nasal stuffiness Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Indications Relief of nasal congestion associated with Acute or chronic rhinitis Common cold Sinusitis Hay fever Other allergies Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Indications (cont’d) May also be used to reduce swelling of the nasal passage and facilitate visualization of the nasal/pharyngeal membranes before surgery or diagnostic procedures Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Nursing Implications Decongestants may cause hypertension, palpitations, and CNS stimulation—avoid in patients with these conditions Patients on medication therapy for hypertension should check with their prescriber before taking over-the-counter decongestants Assess for drug allergies Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nasal Decongestants: Nursing Implications (cont’d) Patients should avoid caffeine and caffeine-containing products Report a fever, cough, or other symptoms lasting longer than a week Monitor for intended therapeutic effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Two Basic Types of Cough Productive cough Congested, removes excessive secretions Nonproductive cough Dry cough Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Antitussives Drugs used to stop or reduce coughing Opioid and nonopioid Used only for nonproductive coughs! May be used in cases where coughing is harmful Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antitussives: Mechanism of Action Opioids Suppress the cough reflex by direct action on the cough center in the medulla Examples: codeine (Robitussin A-C, Dimetane-DC) hydrocodone Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antitussives: Mechanism of Action (cont’d) Nonopioids Suppress the cough reflex by numbing the stretch receptors in the respiratory tract and preventing the cough reflex from being stimulated Examples: benzonatate (Tessalon Perles) dextromethorphan (Vicks Formula 44, Robitussin-DM) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antitussives: Indications Used to stop the cough reflex when the cough is nonproductive and/or harmful Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antitussives: Adverse Effects benzonatate Dizziness, headache, sedation, nausea, and others dextromethorphan Dizziness, drowsiness, nausea Opioids Sedation, nausea, vomiting, lightheadedness, constipation Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Antitussives: Nursing Implications (cont’d) Report any of the following symptoms to the caregiver: Cough that lasts more than a week A persistent headache Fever Rash Antitussive drugs are for nonproductive coughs Monitor for intended therapeutic effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response 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 central nervous system depression, and it is not an opioid. Guaifenesin is an expectorant that is used to thin excessive mucus, which this patient does not have. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Expectorants Drugs that aid in the expectoration (removal) of mucus Reduce the viscosity of secretions Disintegrate and thin secretions Example: guaifenesin (Mucinex) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Expectorants: Mechanisms of Action Reflex stimulation Direct stimulation Final result: thinner mucus that is easier to remove Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Expectorants: Mechanism of Action (cont’d) Reflex stimulation Drug causes irritation of the GI tract Loosening and thinning of respiratory tract secretions occur in response to this irritation Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Expectorants: Mechanism of Action (cont’d) Direct stimulation The secretory glands are stimulated directly to increase their production of respiratory tract fluids Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Expectorants: Drug Effects By loosening and thinning sputum and bronchial secretions, the tendency to cough is indirectly diminished Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Expectorants: Nursing Implications Expectorants should be used with caution in the elderly or those 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 a week Monitor for intended therapeutic effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Herbal Products: Echinacea Reduces symptoms of the common cold and recovery time Adverse effects Dermatitis GI disturbance Dizziness Headache Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response 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. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.