Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Drugs Affecting Gastrointestinal
Secretions
Chapter 57
Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Underlying Causes of GI Disorders
•
Dietary Excess
•
Stress
•
Hiatal Hernia
•
Esophageal Reflux
•
Adverse Drug Effects
•
Peptic Ulcer Disease
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Effect of Drugs on GI Secretions
•
Decrease GI secretory activity
•
Block the action of GI secretions
•
Form protective coverings on the GI lining to prevent
erosion from GI secretions
•
Replace missing GI enzymes that the GI tract or ancillary
glands and organs can no longer produce
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Drugs Used in the Treatment of GERD &
Ulcers
•
Histamine-2 (H
2
) Antagonists
–
Block the release of hydrochloric acid in response to
gastrin
•
Antacids
–
Interact with acids at the chemical level to neutralize
them
•
Proton Pump Inhibitors
–
Suppress the secretion of hydrochloric acid into the
lumen of the stomach
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Drugs Used in the Treatment of GERD &
Ulcers (cont.)
•
Antipeptic Agents
–
Coat any injured area in the stomach to prevent
further injury from acid
•
Prostaglandins
–
Inhibit the secretion of gastrin and increase the
secretion of the mucous lining of the stomach,
providing a buffer
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Sites of Actions of Drugs Affecting
Gastrointestinal Secretions
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Peptic Ulcer Disease
•
Definition
–
Erosions in the lining of the stomach and adjacent
areas of the GI tract
•
Symptoms
–
Gnawing, burning pain, often occurring after meals
•
Cause
–
Bacterial infection by
Helicobacter pylori
bacteria
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Histamine-2 (H
2
) Antagonists
•
Cimetidine (Tagamet)
•
Famotidine (Pepcid)
•
Nizatidine (Axid)
•
Ranitidine (Zantac)
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Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Histamine-2 (H
2
) Antagonists (cont.)
•
Indications (cont.)
–
Treatment of erosive gastroesophageal reflux
–
Relief of symptoms of heartburn, acid indigestion,
and sour stomach (OTC preparations)
•
Pharmacokinetics
–
Readily absorbed after oral administration
–
Metabolized in the liver and excreted in urine
•
Contraindications
–
Known allergy
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