Chapter 14 Antihistamines and Nasal Decongestants.
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Chapter 14
Antihistamines and Nasal Decongestants
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Common Cold
Virus infection Rhinovirus Influenza virus
Initiates the inflammatory response
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Common Cold
Cough reflex Irritant stimulates sensory receptors Removes
Respiratory secretions Foreign object
(continued)
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Inflammatory Response
Mucosal irritation Release of several inflammatory and
vasoactive substances Histamine Dilating small blood vessels in the nasal
sinuses Produces nasal congestion
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Symptomatic Treatment
Combined use of: Antihistamines, nasal decongestants,
antitussives, and expectorants
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Antihistamines and Nasal Decongestants
Compete with histamine for receptor sites
Two histamine receptors H1 (histamine 1) H2 (histamine 2)
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Vasodilatation—GI effects
Increase gastrointestinal and respiratory secretions
Increase capillary permeability The binding of H1 and H2 blockers to
histamine receptors prevent histamine stimulation
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H1 Antagonists
Respiratory antihistamines Effects
Antihistaminic Mild anticholinergic
Parasympathetic nervous system Sedative
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Antihistamines
Antihistamines Cardiovascular: small blood vessels
Histamine effects Dilation Permeability
Antihistamine effects Prevent dilation Prevent increased permeability
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Skin Prevent itching Wheal and flare
Anticholinergic Drying effect
Sedative Drowsiness
Antihistamines
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(continued)
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Antihistamines
Management of: Nasal allergies Seasonal or perennial allergic rhinitis Allergic reactions Motion sickness
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(continued)
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Antihistamines
More effective in prevention Give early
Prevent binding of histamine receptors
(continued)
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Classes of Antihistamines
Two types Traditional: sedating Nonsedating
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Traditional Antihistamines
Older Work both peripherally and centrally Anticholinergic properties Examples: diphenhydramine (Benadryl)
and chlorpheniramine (Chlor-Trimeton)
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Nonsedating/Peripherally Acting
Antihistamines Work peripherally
Eliminate sedation Longer duration of action
Increases compliance Examples: fexofenadine (Allegra) and
loratadine (Claritin)
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Antihistamines: Nursing Implications
Assess allergy history Contraindicated
Asthma attacks Chronic obstructive pulmonary disease Cardiovascular disease
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Client Teaching
Instruction for traditional/sedating antihistamines
Avoid driving No alcohol No central nervous system depressants
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Nasal Decongestants
Two main types are used: Adrenergics (largest group)
Constrict dilated blood vessels • Nasal mucosa
Corticosteroids Reduce inflammation
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Goal of Nasal Decongestants
To reduce congestion Two dosage forms
Oral Topical
Nasal spray
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Oral Decongestants
Prolonged effects Less potent No rebound congestion Exclusively adrenergics Example: pseudoephedrine (Sudafed)
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Topical Decongestants
Adrenergics Prompt onset Sustained use–rebound congestion
Both adrenergics and steroids Potent; work well
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Nasal Steroids
Anti-inflammatory Decrease inflammation Relieve nasal congestion
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Nasal Decongestants
Intranasal steroids Beclomethasone
dipropionate Beconase Vancenase
Flunisolide(Nasalide)
Adrenergics Ephedrine (Vicks) Naphazoline
(Privine) Oxymetazoline
(Afrin) Phenylephrine
(Neosynephrine)
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Nasal Decongestants: Side Effects
Adrenergics Nervousness Insomnia Palpitations Tremors
Steroids Local mucosal dryness and irritation
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Treatment with Nasal Decongestants
Acute or chronic rhinitis Common cold Sinusitis Hay fever Other allergies
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Nasal Decongestants: Nursing Implications
Avoid decongestants in the following clients:
Heart disease Hypertensive disease
Respiratory disease Assess for drug allergies
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