Ppt chapter 57

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

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

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

Drugs Used in the Treatment of Ulcers
• Histamine-2 (H2) 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

Drugs Used in the Treatment of 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

Sites of Actions of Drugs Affecting
Gastrointestinal Secretions

Histamine-2 (H2) Antagonists
• Actions
– Selectively block histamine-2 receptor sites
– This blocking leads to a reduction in gastric acid secretion
and reduction in overall pepsin production
• Indications
– Short-term treatment of active duodenal ulcer or benign
gastric ulcer
– Treatment of pathological hypersecretory conditions such
as Zollinger–Ellison syndrome
– Prophylaxis of stress-induced ulcers and acute upper GI
bleeding in critical patients

Histamine-2 (H2) 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

Histamine-2 (H2) Antagonists (cont.)
• Caution
– Pregnancy or lactation
– Hepatic or renal dysfunction
• Adverse Effects
– GI effects
– CNS effects
– Cardiac arrhythmias and hypotension
• Drug-to-Drug Interactions
– Warfarin, phenytoin, beta blockers, alcohol, quinidine, lidocaine,
theophylline, chloroquine, benzodiazepines, nifedipine,
pentoxifylline, tricyclics, procainamide, and carbamazepine

Question
Drugs act in several ways on the secretions of the GI tract.
Which action affects the GI secretions least?
A. Decreases secretory activity
B. Blocks secretions
C. Replaces secretions
D. Prevents erosions

Answer
C. Replaces secretions
Rationale: The effects 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

Antacids
• Actions
– Neutralize stomach acid by direct chemical reaction
• Indications
– Symptomatic relief of upset stomach associated with
hyperacidity, as well as hyperactivity
– Allergy
• Caution
– Any condition that can be exacerbated by electrolyte
imbalance
– GI obstruction

Antacids (cont.)
• Adverse Effects
– Relate to their effects on acid-base levels and
electrolytes
– Rebound acidity
– Alkalosis
– Hypercalcemia
– Constipation or diarrhea
– Hypophosphatemia
– Affect the absorption of many other drugs

Proton Pump Inhibitors
• Actions
– Act at specific secretory surface receptors to prevent the final
step of acid production and thereby decrease the level of acid in
the stomach
• Indications
– Short-term treatment of active duodenal ulcers, GERD, erosive
esophagitis, and benign active gastric disease
– Long-term treatment of pathological hypersecretory conditions
– Acid labile, rapidly absorbed in the GI tract
– Metabolized in the liver and excreted in the urine

Proton Pump Inhibitors (cont.)
– Allergy
• Caution
• Adverse Effects
– CNS effects
• Dizziness, headache, asthenia, vertigo, insomnia,
apathy

Proton Pump Inhibitors (cont.)
• Adverse Effects (cont.)
– GI Effects
• Diarrhea, abdominal pain, and tongue atrophy
– Upper respiratory tract symptoms
• Cough, stuff nose, hoarseness, and epistaxis
– Other
• Rash, alopecia, pruritis, dry skin, back pain, and
fever

Antipeptic Agent
• Actions
– Forms an ulcer-adherent complex at duodenal ulcer sites,
protecting the sites against acid, pepsin, and bile salts
• Indications
– Promote ulcer healing
– Rapidly absorbed, metabolized in the liver, and excreted in
feces
– Allergy
– Renal failure

Antipeptic Agent (cont.)
• Caution
• Adverse Effects
– GI effects – Constipation, diarrhea, nausea,
indigestion, gastric discomfort, dry mouth
– Dizziness
– Sleepiness
– Vertigo
– Skin rash
– Back pain

Antipeptic Agent (cont.)
– Aluminum salts
– Phenytoin, fluoroquinolone, or penicillamine

Prostaglandin
• Actions
– Inhibits gastric acid secretion and increases bicarbonate
and mucous production in the stomach
• Indications
– Prevention of NSAID-induced gastric ulcers
– Treatment of duodenal ulcers
– Rapidly absorbed from GI tract, metabolized in the liver,
and excreted in the urine
– Pregnancy

Prostaglandin (cont.)
• Caution
– Lactation
• Adverse Effects
– GI effects – Nausea, diarrhea, abdominal pain,
flatulence, vomiting, dyspepsia, and constipation
– GU effects – Miscarriages, excessive bleeding,
spotting, cramping, hypermenorrhea, dysmenorrhea,
and other menstrual disorders

Question
Please answer the following statement as true or false.
There is a drug-drug interaction between the antipeptides
and penicillin.

Answer
False
Rationale: Drug-to-drug interactions include aluminum
salts, phenytoin, fluoroquinolone, or penicillamine.

Patients Who May Require Digestive
Enzyme Supplements
• Saliva Supplements
– Stroke
– Salivary gland disorder
– Extreme surgery of the head and neck
• Pancreatic Enzyme Supplements
– Common duct problems
– Pancreatic disease
– Cystic fibrosis

Digestive Enzymes
• Actions
– Saliva substitute – Contains electrolytes and
carboxymethylcellulose to act as a thickening agent
in dry mouth conditions
– Pancreatic enzymes are replacement enzymes that
help the digestion and absorption of fats, proteins,
and carbohydrates
• Indications
– Replacement therapy

Digestive Enzymes (cont.)
– Saliva – Allergy
– Pancreatic enzymes - Allergy
• Caution
– Saliva – CHF, hypertension, or renal failure
– Pancreatic enzyme – Pregnancy and lactation

Digestive Enzymes (cont.)
• Adverse Effects
– Saliva – Complications from abnormal electrolytes –
increased levels of magnesium, sodium, or potassium
– Pancreatic enzyme – GI irritation, nausea, abdominal
cramps, and diarrhea

Use of Agents Affecting Gastrointestinal
Secretions Across the Lifespan

Prototype Histamine-2 (H2) Antagonists

Prototype Antacids

Prototype Proton Pump Inhibitors

Prototype Digestive Enzymes

Question
What H2 antagonist has been associated with
antiandrongenic effects?
A. Famotidine
B. Cimetidine
C. Nizatidine
D. Ranitidine

Answer
B. Cimetidine
Rationale: Cimetidine was the first drug in this class to be
developed. It has been associated with antiandrongenic
effects, including gynecomastia and galactorrhea.

Nursing Considerations for Histamine-2
(H2) Antagonists
• Assessment: History and Physical Exam
• Nursing Diagnosis
• Implementation
• Evaluation

Nursing Considerations for Antacids
• Implementation
• Evaluation

Nursing Considerations for Proton Pump
Inhibitors
• Implementation
• Evaluation

Nursing Considerations for Antipeptic
Agent
• Implementation
• Evaluation

Nursing Considerations for Prostaglandin
• Implementation
• Evaluation

Nursing Considerations for Digestive
Enzymes
• Implementation
• Evaluation

Ppt chapter 57

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