Respiratory Pharmacology

1
Respiratory Pharmacology

• Exam I

2
Antihistamines
3
H1 Antagonists1st Generation
ZZZZ

• Overview
• Penetrate CNS gt High Sedative
• Anticholinergic
• Antiemetic
• Cognitive decline in the ELDERLY
• Diphenhydramine (Benadryl)
• Clinical Use (Topical, Oral, IV, IM)
• Motion sickness
• Antitussive
• Night time Sleep Aid
• Topical Antipruritic
• Type I IgE-mediated hypersensitivity rxns
• Topical w/Maalox canker sores in children

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H1 Antagonists1st Generation

• Doxylamine
• Clinical Use OTC
• Night time Sleep Aid
• Dimenhydrinate (Dramamine)
• Clinical Use OTC
• Nausea Vomiting
• Dizzyness Vertigo
• Meclizine (Antivert) Long-acting gt 12-24hrs
• Clinical Use
• Motion sickness

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H1 Antagonists1st Generation

• Hydroxyzine
• Clinical Use
• Motion sickness PRURITUS
• Antianxiety
• Sedation Pre/post-op
• Promethazine
• Clinical Use
• Motion sickness
• Antianxiety
• Sedation Pre/post-op
• Type I IgE-mediated hypersensitivies (Allergic
  Rhinitis)
• Antiemetic Prevent N V assoc. w/ General
  Anesthetics
• Block DA receptors in Chemoreceptor Trigger Zone
  (CTZ)
• Caution Can ? Seizure Threshold

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H1 Antagonists1st Generation

• Chloropheniramine
• Brompheniramine
• Available only w/ other ingredients
• Pseudoephedrine, APAP, dextromethorphan
• Cryproheptadine
• SN Best to treat ITCHING
• SE
• Weight Gain
• Block 5-HT2 receptors

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H1 Antagonists1st Generation (Ophthalmics)
Allergic Conjunctivitis

• Ophthalmics
• Used for ITCHING w/
• SE Sedation and Anti-SLUD
• Caution According to Dr. Walters, DUH!
• w/ other Sedating Drugs
• Narrow Angle Glaucoma
• Azelastine (Nasal spray)
• Olopatadine
• H1 antagonist Inhibits Degranulation

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H1 Antagonists2st Generation
Hello NURSE!

• Overview
• Does NOT penetrate CNSgtPoorly/NOT Sedative
• NO Anti-SLUD activity!
• NO Antiemetic activity!
• Fexofenadine (Allegra)
• Cetirizine (Zyrtec) Long-acting gt 12-24hrs
• Active metabolite of Hydroxyzine
• Slightly Sedative

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H1 Antagonists2st Generation

• Loratadine (Claritin)
• SE ? Appetite gt Weight Gain
• Desloratadine (Clarinex)
• Isomer of Loratadine
• ß Agonist, Cromolyn, Nedocromil
• All have antihistamine activity by
• Blocking Degranulation of MAST CELLS!

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H2 Antagonists

• Overview
• MOA
• Blocks H2 component of Allergic Response
• Inhibits GASTRIC ACID secretion
• Clinical Use
• Duodenal and gastric ULCERS
• SE
• Headaches
• Diarrhea / Constipation
• Drowsiness
• CNS rare but possible in the elderly

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H2 Antagonists

• Cimetidine (Tagamet) - Oral IV/IM
• BINDS to cytochrome P450
• Significant inhibitor of Rx metabolism
• Side Effects
• ? Estradiol levels in men (? P450 activity)
• ? Prolactin gt GYNECOMASTIA
• Caution in tx of ZES
• TUMOR of Pancreatic Islets ??? Acid secretion
• Inhibits 5 a reductase (? DHT)
• Inhibits Binding of DHT
• Impotence ?Libido
• Caution Weakly acidic ? Rx absorption

Only in High Doses
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H2 Antagonists

• Ranitidine (Zantac) - Oral IV/IM
• Famotidine (Pepcid) OTC (except IV)
• Pepcid Complete
• Famotidine CaCO3 Magnesium Hydroxide
• Nizatidine - Oral

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Nasal Decongestants

• Phenylephrine
• Clinical Use
• IV for SHOCK
• Systemic ? BP
• IV for Supraventricular Tachycardia
• Baro-reflex gt ? HR
• Mydriatic pupillary dilation
• Contracts dilator muscles
• Added to Local Anesthetics
• Vasoconstriction keep anesthetic local

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Nasal Decongestants

• Oxymetazoline
• Clinical Use Ocular decongestant
• Available in a drop or spray
• EXCEPTION a2 agonist
• Pseudoephedrine (Sudafed)
• Available in tablets, oral liquid, pediatric
  drops

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Expectorant

• Guaifenesin (Robitussin)
• MOA
• Irritant of the lining of the airway
• ? Secretions gt Helps to dilute and break up FLEM
• ? VISCOITY
• ? Surface Tension
• Robitussin DM
• Dextromophorphan guaifenesin