Chapter 14 Antihistamines and Nasal Decongestants.

Chapter 14

Antihistamines and Nasal Decongestants

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

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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

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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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Antihistamines

Management of: Nasal allergies Seasonal or perennial allergic rhinitis Allergic reactions Motion sickness

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Antihistamines

More effective in prevention Give early

Prevent binding of histamine receptors

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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

Chapter 14 Antihistamines and Nasal Decongestants.

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histamine stimulation

nasal congestion slide

histamine receptors

antihistamines cardiovascular

antihistamines management