Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved. Chapter 20: Drugs for Tx Allergic Rhinitis DH206: Pharmacology Lisa Mayo, RDH, BSDH Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Jan 06, 2018
Chapter 20: Drugs for Tx Allergic Rhinitis
DH206: PharmacologyLisa Mayo, RDH, BSDH
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Copyright © 2011, 2007 Mosby, Inc., an affiliate of Elsevier. All rights reserved.
Chapter 18 Outline1. Histamine 2. Antihistamines3. Intranasal Corticosteroids
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Chapter 18 Outline1. Histamine
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Histamine Basics•All human synthesize histamine•Stored in mast cells in intestinal mucosa•Amt released determines person’s response•There are 3 types of histamine in human
body (next slide)
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Histamine Basics3 histamine receptors (none have clinical use)
1. H1: located on smooth muscle of GI tract, heart, vein, capillaries, bronchi Vasodilation (↓BP – could lead to hypotension) Bronchoconstriction Pain or itching in cutaneous nerve endings (histamine
binds to receptors on local sensory nerve endings) ↑ production of nasal & bronchial mucus
2. H2: located on brain, stomach, heart, blood vessels ↑ gastric acid secretion Vasodilation
3. H3: on mast cells Stimulation inhibits histamine release
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(A): Initial exposure to allergen, IgE produced & binds to mast cells
(B) Subsequent exposure: allergen binds to IgE on the mast cell
(C) Mast cells release histamine, leukotriene, prostaglandin
↓ cause bronchoconstriction, vasodilation, mucus production
ALLERGY RXN
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NBQHistamine is released largely in part by:
a. Macrophagesb. Enteroendocrine cellsc. Lymphocytesd. Neutrophilse. Mast cells
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NBQHistamine is released largely in part by:
a. Macrophagesb. Enteroendocrine cellsc. Lymphocytesd. Neutrophilse. Mast cells
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2. Antihistamines
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Histamine Basics• Antihistamines: Block histamine receptors
▫ H1-blockers used to tx allergic rxns & motion sickness▫ Adverse rxns due to binding of antihistamines on other
organs▫ Anaphylactic rxn
Histamine causes more vasodilation & capillary permeability = leads to a further decrease in BP = then shock & cardiac collapse
Which drug do we give to tx? Why?EPI ANTIHISTAMINEα1-receptors Causes
vasoconstriction (↑BP)
ß2-receptors Cause bronchodilation
Histamine Antagonist
Antagonize bronchoconstriction
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NBQSerotonin is a preferred vasoactive mediator with actions similar to those of:
a. Heparinb. Thrombinc. Acetylcholined. Histamine
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NBQSerotonin is a preferred vasoactive mediator with actions similar to those of:
a. Heparinb. Thrombinc. Acetylcholined. Histamine
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•Relieve S&S of histamine release in body•These drugs ONLY effective on H1 receptors
in body (H2 assoc. with effects in stomach – CH15)▫Oral▫Parental▫Topical creams, lotions, sprays▫Nasal spray for relief of allergic rhinitis ▫Eye drops for itching, watery eyes
Antihistamines (H1-Receptor Antagonists)
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First-generation drugs: adverse rxns related to anticholinergic activity (xerostomia, sedation)
Antihistamines (H1-Receptor Antagonists)
1st-Generation AntihistaminesDiphenhydramine(Benadryl)Chlorpheniramine(Chlor-Trimeton)Hydroxyzine(Atarax, Vistaril)Dexchlorpheniramine(Prolarmine)Promethazine(Phenergan)Clemastine(Tavist)Dimenhydrinate(Dramamine)Meclizine(Antivert)
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Second-generation drugs▫Less anticholinergic activity: not as many
adverse rxns
Antihistamines (H1-Receptor Antagonists)
2nd-Generation Antihistamines
Fexofenadine(Allegra)
Cetirizine(Zyrtec)
Loratadine(Claritin)
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Allegra &
Claritin 2nd gen.
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Antihistamines (H1-Receptor Antagonists)
ACTION EFFECTS IN BODY DRUGSAntihistamini
c ActionAllergy relief Relieve itching
Benadryl is most effective
Anticholinergic Action
Sedation, Dry up secretionsBronchodilationDilate eyesRelieve vertigo & motion sickness
Meclizine(Antivent,Bonine)Promethazine(Phenergan) Dimenhydrinate(Dramamine)
Adverse Rxns related to these effects
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Intranasal antihistamines▫All intranasal’ s usually taken in combo with oral
sinus med
Antihistamines (H1-Receptor Antagonists)
Intranasal AntihistamineAzelastine(Astelin) Allergic rhinitisOxymetazoline(Afrin)Phenylephrine(Sinex)
α1-antagonist: constrict blood vessels3-5 days after use – will have re-bound action & symptoms worse than before
Olopatadine hydrocholoride(Patanase)
Allergic rhinitis
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NBQWhich of the following adverse effects occurs with antihistamines?
a. Dry mouthb. Increased salivationc. Dry skind. Moist skin
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NBQWhich of the following adverse effects occurs with antihistamines?
a. Dry mouthb. Increased salivationc. Dry skind. Moist skin
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NBQWhich of the following antihistamines has anticholinergic effects?
a. Loratadineb. Fexofenadinec. Diphenhydramined. Azelastine
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NBQWhich of the following antihistamines has anticholinergic effects?
a. Loratadineb. Fexofenadinec. Diphenhydramined. Azelastine
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3. Intranasal Corticosteroids
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Intranasal CorticosteroidsIntranasal CorticosteroidBudesonide(Rhinocort)Ciclesonide(Omnaris)Fluticasone propionate(Flonase)Mometasone furoate(Nasonex)
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