ppt chapter 36

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Chapter 36

Drugs Affecting the Upper Gastrointestinal Tract

Chapter 36

Drugs Affecting the Upper Gastrointestinal Tract


Physiology Physiology • The upper GI tract consists of the mouth, oropharynx,

esophagus, stomach, and duodenum (small intestine).

• Digestion begins in the mouth.

• Peristalsis is a rhythmic movement of contraction and expansion of the smooth muscle, propels the food toward the stomach.

• Gastric secretions are regulated primarily by the parasympathetic nervous system.

• Vomiting of GI contents is controlled by the vomit center (VC) in the medulla of the brain.

• Additionally, the VC can be stimulated when the chemoreceptor trigger zone (CTZ) is stimulated.


Cells Within the StomachCells Within the Stomach


Pathophysiology Pathophysiology • Gastroesophageal reflux disease (GERD) allows stomach

acid to back up into the esophagus. Four major symptoms are heartburn, regurgitation, dysphagia, and waterbrash.

• Helicobacter pylori infection (H. pylori) is a gram-negative, spiral bacterium that weakens the protective mucous lining of the stomach and duodenum.

• Peptic ulcer disease (PUD) is a general term that refers to ulcer formation in the esophagus, stomach, or duodenum.

• Pancreatitis occurs when the digestive enzymes production is reduced or no longer occurs.

• Obesity is where the BMI exceeds the normal range.

• Nausea and vomiting is caused by stimulation of the chemoreceptors in the brain and GI tract.


Proton Pump Inhibitors Proton Pump Inhibitors

• The secretion of gastric acid can be suppressed by inhibiting the enzyme system at the secretory surface of the gastric parietal cell.

• These drugs block the final step of gastric acid production.

• Prototype drug: omeprazole (Prilosec)


Omeprazole: Core Drug Knowledge Omeprazole: Core Drug Knowledge

• Pharmacotherapeutics

– Treatment of heartburn and GERD

• Pharmacokinetics

– Administered: oral. Metabolism: liver. Absorption: small intestines. Excreted: urine and feces.

• Pharmacodynamics

– Suppresses the last phase of gastric acid production by suppressing the H+/K+ ATPase enzyme system


Omeprazole: Core Drug Knowledge (cont.)Omeprazole: Core Drug Knowledge (cont.)

• Contraindications and precautions

– Hypersensitive

• Adverse effects

– Headache and diarrhea

• Drug interactions

– Other drugs that also are metabolized through the cytochrome P-450 pathway


Omeprazole: Core Patient Variables Omeprazole: Core Patient Variables • Health status

– Determine the clinical indication for therapy.

• Life span and gender

– Pregnancy Category C drug

• Lifestyle, diet, and habits

– Assess diet and smoking habits.

• Environment

– Assess the environment where the drug will be given.

• Culture and inherited traits

– Longer duration of action in Asians


Omeprazole: Nursing Diagnoses and Outcomes Omeprazole: Nursing Diagnoses and Outcomes

• Altered Comfort related to symptoms of GERD, PUD, or chronically elevated acid production

– Desired outcome: Drug therapy will relieve the symptoms from the GI disorder.

• Imbalanced Nutrition: Less than Body Requirements related to symptoms of GERD, PUD, or chronically elevated acid production

– Desired outcome: Drug therapy will allow adequate dietary intake.

• Collaborative Problem: H. pylori infection

– Desired outcome: Treatment regimen to eradicate H. pylori will be effective, with minimal adverse effects.


Omeprazole: Planning and InterventionsOmeprazole: Planning and Interventions

• Maximizing therapeutic effects

– Take medication daily.

– Be sure the patient does not crush or chew the capsule.

• Minimizing adverse effects

– Suggest calcium citrate supplementation for elderly patients on long-term therapy


Omeprazole: Teaching, Assessment, and EvaluationOmeprazole: Teaching, Assessment, and Evaluation

• Patient and family education

– Teach patients to take omeprazole 1 hour before meals.

– Advise patients to contact the health care provider immediately if they experience persistent diarrhea.

• Ongoing assessment and evaluation

– Omeprazole therapy is effective when the symptoms of GERD, PUD, or hypersecretory conditions are controlled or the duodenal ulcer is healed.


QuestionQuestion

• What is the most common adverse effect(s) of omeprazole?

– A. Headache

– B. Dizziness

– C. Diarrhea

– D. Both A and C

– E. All of the above


AnswerAnswer

• D. Both A and C

• Rationale: Omeprazole is generally well tolerated. The most common adverse effects are headache and diarrhea.


Histamine-2 Receptor Antagonists Histamine-2 Receptor Antagonists

• H2 RAs block the effect of histamine at H2 receptors, particularly those in the parietal cells of the stomach.

• By blocking histamine at the parietal cells, these drugs inhibit gastric acid secretion in all phases and other secretions caused by histamine.

• Inhibit the fasting secretions that occur during the night, as well as secretions stimulated by food, insulin, caffeine, pentagastrin, and betazole.

• These drugs also reduce the volume and concentration of gastric secretions.

• Prototype drug: ranitidine (Zantac)


Ranitidine: Core Drug Knowledge Ranitidine: Core Drug Knowledge


– Treatment of ulcers


– Administered: oral. Distribution: dd. Metabolism: liver. Excreted: kidneys.


– Inhibits both daytime and nocturnal basal gastric acid secretions


Ranitidine: Core Drug Knowledge (cont.)Ranitidine: Core Drug Knowledge (cont.)


– Hypersensitive

• Adverse effects

– Headache, blood count changes, GI effects; hepatocellular, cholestatic, or mixed hepatitis


– Favorable drug interaction profile because it does not inhibit the cytochrome P-450 system


Ranitidine: Core Patient Variables Ranitidine: Core Patient Variables

• Health status

– Assess symptoms prior to administration of the drug.


– Pregnancy Category B drug


– Assess diet and smoking habits.

• Environment



– Assess cultural influences on diet.


Ranitidine: Nursing Diagnoses and Outcomes Ranitidine: Nursing Diagnoses and Outcomes

• Chronic Pain related to alteration in the gastric mucosa, ulceration, or irritation

– Desired outcome: The patient will report decreased pain while receiving drug therapy.

• Acute Pain related to adverse drug effects, such as headache

– Desired outcome: The patient will not experience adverse effects while taking ranitidine.


Ranitidine: Nursing Diagnoses and Outcomes (cont.)Ranitidine: Nursing Diagnoses and Outcomes (cont.)

• Risk for Injury related to drug-induced somnolence, dizziness, confusion, or hallucinations

– Desired outcome: The patient will not suffer injury from adverse effects of drug therapy.

• Diarrhea related to adverse effects of drug therapy

– Desired outcome: The patient will remain well hydrated and elimination patterns will remain within normal parameters.


Ranitidine: Planning and InterventionsRanitidine: Planning and Interventions


– If both ranitidine and antacids are prescribed, give them at least two hours apart to prevent decreased absorption of ranitidine.


– Monitor serum trough levels in patients with renal or hepatic impairment.

– Administer IV ranitidine slowly to prevent hypotension and cardiac arrhythmias.


Ranitidine: Teaching, Assessment, and EvaluationRanitidine: Teaching, Assessment, and Evaluation


– Instruct patients to take the drug exactly as directed.

– Caution patients not to take a double dose if a dose is missed.


– During long-term ranitidine therapy, the patient’s blood count should be monitored to detect changes from baseline.


QuestionQuestion

• Ranitidine is metabolized by the cytochrome P-450 system.

– A. True

– B. False


AnswerAnswer

• B. False

• Rationale: Ranitidine has a favorable drug interaction profile because it does not inhibit the cytochrome P-450 system.


Antacids Antacids

• Antacids are drugs that increase the gastric pH.

• These preparations are used for various upper GI disorders, including symptoms of GERD, esophagitis, hiatal hernia, gastritis, and PUD.

• Antacids are composed of inorganic salts.

• Antacids include aluminum hydroxide with magnesium hydroxide, aluminum, magnesium, calcium, and sodium bicarbonate.

• Prototype drug: aluminum hydroxide with magnesium hydroxide (Maalox, Mylanta)


Aluminum Hydroxide: Core Drug Knowledge Aluminum Hydroxide: Core Drug Knowledge


– Relieve symptoms associated with GERD


– Administered: oral. Excreted: feces. Onset: rapid.


– Raises the gastric pH in the stomach and duodenal bulb


Aluminum Hydroxide: Core Drug Knowledge (cont.)Aluminum Hydroxide: Core Drug Knowledge (cont.)


– Caution in patients with recent massive GI bleed

• Adverse effects

– Osteomalacia, encephalopathy, and rebound increased gastric acid production


– Drug interactions caused by decreased gastric acid


Aluminum Hydroxide: Core Patient Variables Aluminum Hydroxide: Core Patient Variables

• Health status

– Assess patient symptoms.


– Assess diet, alcohol intake, and smoking.

• Environment



Aluminum Hydroxide: Nursing Diagnoses and Outcomes Aluminum Hydroxide: Nursing Diagnoses and Outcomes • Chronic Pain related to alteration in the gastric mucosa,

ulceration, or irritation

– Desired outcome: The patient will report that pain has decreased while on drug therapy.

• Potential Complication: Electrolyte Imbalance related to hypophosphatemia, hypermagnesemia, or hyperalbuminemia secondary to drug therapy

– Desired outcome: The patient’s electrolyte levels will remain within normal limits.

• Diarrhea or Constipation secondary to drug therapy

– Desired outcome: The patient’s elimination patterns will remain within normal parameters.


Aluminum Hydroxide: Planning and InterventionsAluminum Hydroxide: Planning and Interventions


– Liquid preparations are usually preferred because of their rapid action.

– Shake suspension.


– Administer 2 hours after other drugs to prevent drug interactions.

– Monitor for signs of acid rebound.


Aluminum Hydroxide: Teaching, Assessment, and EvaluationAluminum Hydroxide: Teaching, Assessment, and Evaluation


– Teach proper drug administration.

– Caution patients not to take the maximum dose for longer than 2 weeks.


– Therapy is considered effective if the patient’s pain is decreased or eliminated, electrolytes remain at normal levels, elimination patterns remain normal, and GI symptoms are controlled.


QuestionQuestion

• A serious adverse effect associated with the use of aluminum hydroxide with magnesium hydroxide is

– A. Electrolyte imbalance

– B. Stress ulcer

– C. Black, tarry stools

– D. Diarrhea


AnswerAnswer

• A. Electrolyte imbalance

• Rationale: The most serious adverse effect is electrolyte imbalance.


Prokinetic Agents Prokinetic Agents

• The prokinetic agents increase the effect of acetylcholine on the GI system.

• Acetylcholine is responsible for normal GI function.

• Prokinetic agents increase peristalsis and gastric emptying.

• Prototype drug: metoclopramide (Reglan)


Metoclopramide: Core Drug Knowledge Metoclopramide: Core Drug Knowledge


– Relieves symptoms of diabetic gastroparesis


– Administered: oral. Metabolism: liver. Excreted: kidneys.


– Mechanism of action is unclear.


Metoclopramide: Core Drug Knowledge (cont.)Metoclopramide: Core Drug Knowledge (cont.)


– GI hemorrhage, perforation, or mechanical obstruction

• Adverse effects

– Restlessness, drowsiness, depression, insomnia, headache, anxiety, dizziness, and confusion


– Levodopa, anticholinergics, and narcotics


Metoclopramide: Core Patient Variables Metoclopramide: Core Patient Variables

• Health status

– Assess symptoms.



• Environment

– Oral given in any environment; IV given in acute care settings


Metoclopramide: Nursing Diagnoses and Outcomes Metoclopramide: Nursing Diagnoses and Outcomes • Risk for Self-Directed Violence secondary to adverse effects of

drug therapy

– Desired outcome: The patient will do no self-harm related to depression from drug therapy.

• Powerlessness related to extrapyramidal effects, Parkinson-like symptoms, or tardive dyskinesia secondary to adverse effects of drug therapy

– Desired outcome: The patient will make decisions regarding own care, treatment, and future (when possible) while on drug therapy.

• Risk for Injury related to drowsiness, fatigue, insomnia, confusion, and hallucination secondary to adverse effects of drug therapy

– Desired outcome: The patient will not suffer injury while on drug therapy.


Metoclopramide: Planning and InterventionsMetoclopramide: Planning and Interventions


– Give oral doses 30 minutes before each meal.

– Do not administer metoclopramide concurrently with anticholinergic drugs.


– Monitor for evidence of depression.

– Withhold the dose and notify the prescriber if Parkinson-like symptoms occur.


Metoclopramide: Teaching, Assessment, and EvaluationMetoclopramide: Teaching, Assessment, and Evaluation• Patient and family education

– Tell patients to take metoclopramide 30 minutes before meals.

– Discuss side effects of drug.

– Caution patients to avoid alcoholic beverages, sedatives, and other CNS depressants.


– With careful monitoring and follow-up assessments, therapy can be considered successful if the patient’s GI complaints diminish.


QuestionQuestion

• To promote optimal effectiveness of the drug, metoclopramide should be given

– A. 30 minutes before meals

– B. At the start of the meal

– C. 30 minutes after the meal

– D. Three times a day without regard to meal times


AnswerAnswer

• A. 30 minutes before meals

• Rationale: Metoclopramide should be given 30 minutes before meals to achieve maximum effectiveness.


Digestive Enzymes Digestive Enzymes

• Digestive enzymes are responsible for breaking down food into forms that can be absorbed easily in the GI tract.

• Replacement of many of these enzymes is not necessary or truly useful because rarely does a deficiency of endogenous enzymes actually cause GI problems.

• Many of the drug preparations of digestive enzymes are combinations of various enzymes, frequently paired with anticholinergics, barbiturates, or antacids.

• Prototype drug: pancrelipase (Pancrease MT, Viokase, Creon, Lipram, Pancrecarb, Panocaps)


Pancrelipase: Core Drug Knowledge Pancrelipase: Core Drug Knowledge


– Replacement therapy for patients with deficient exocrine pancreatic secretions


– Unknown


– Pancrelipase contains the enzymes lipase, protease, and amylase, which are responsible for the final phase of digestion


Pancrelipase: Core Drug Knowledge (cont.)Pancrelipase: Core Drug Knowledge (cont.)


– Hypersensitive

• Adverse effects

– Nausea, abdominal cramps, and diarrhea


– Antacids calcium carbonate and magnesium hydroxide, iron preparations


Pancrelipase: Core Patient Variables Pancrelipase: Core Patient Variables

• Health status

– Assess health history.


– Pregnancy Category C drug

• Environment



– Consider religious affiliation.


Pancrelipase: Nursing Diagnoses and Outcomes Pancrelipase: Nursing Diagnoses and Outcomes

• Imbalanced Nutrition: Less than Body Requirements related to impaired digestion secondary to insufficient pancreatic enzymes

– Desired outcome: The patient’s nutrient absorption will be adequate to meet body needs while on drug therapy.

• Risk for Pain, acute abdominal, secondary to adverse effects of drug therapy

– Desired outcome: The patient will not develop pain as an adverse effect of drug therapy.


Pancrelipase: Planning and InterventionsPancrelipase: Planning and Interventions


– Brands of pancrelipase should not be changed.

– Administer antacids or H2-receptor antagonists, if prescribed.


– Be sure to administer or make sure the patient is administering pancrelipase exactly as prescribed to prevent excessive dosing.


Pancrelipase: Teaching, Assessment, and EvaluationPancrelipase: Teaching, Assessment, and Evaluation


– Tell patients to take the drug every time they eat.

– Urge patients to notify the prescriber of any abdominal pain, diarrhea, nausea, or return of steatorrhea.


– Assess patients taking pancrelipase for decreased steatorrhea, weight gain, and improved nutritional status.


QuestionQuestion

• Patients who are hypersensitive to _______ should not use pancrelipase.

– A. Eggs

– B. Soy

– C. Dairy

– D. Pork


AnswerAnswer

• D. Pork

• Rationale: Pancrelipase is contraindicated in patients who are hypersensitive to pork protein or enzymes, because the drug is derived from pork.


Drugs for Weight Management Drugs for Weight Management

• Lipase inhibitors and anorexiants are drug classes for the management of obesity.

• Lipase inhibitors

– Used specifically for long-term weight reduction

• Prototype drug: orlistat (Xenical)


Orlistat: Core Drug Knowledge Orlistat: Core Drug Knowledge


– Manages obesity


– Administered: oral. Protein bound. Metabolism: liver. Excreted: feces.


– Reversible lipase inhibitor


Orlistat: Core Drug Knowledge (cont.)Orlistat: Core Drug Knowledge (cont.)


– Chronic malabsorption syndrome or cholestasis

• Adverse effects

– Oily spotting, flatus with discharge of stool, increased defecation, and fecal incontinence


– Fat-soluble vitamins


Orlistat: Core Patient Variables Orlistat: Core Patient Variables

• Health status

– Assess BMI and cardiac risk factors.




– Assess diet history.

• Environment

– Given at home


Orlistat: Nursing Diagnoses and Outcomes Orlistat: Nursing Diagnoses and Outcomes

• Imbalanced Nutrition: More than Body Requirements

– Desired outcome: The patient will lose weight during drug therapy.

• Risk for Imbalanced Nutrition: Less than Body Requirements related to impaired absorption of fat-soluble vitamins during drug therapy

– Desired outcome: The patient will not have serious vitamin deficiencies while taking drug therapy.


Orlistat: Nursing Diagnoses and Outcomes (cont.) Orlistat: Nursing Diagnoses and Outcomes (cont.)

• Risk for Bowel Incontinence related to adverse effects of drug therapy

– Desired outcome: Bowel incontinence will not occur or will be minimal and transient.

• Risk for Diarrhea related to adverse effects of drug therapy

– Desired outcome: Diarrhea will not occur or will be minimal and transient.


Orlistat: Planning and InterventionsOrlistat: Planning and Interventions


– Ensure that the patient takes orlistat with all meals that contain fat.

– The patient should also be encouraged to participate in exercise while on drug therapy.


– Advise the patient to take a multivitamin that contains fat-soluble vitamins to prevent imbalances from drug therapy.


Orlistat: Teaching, Assessment, and EvaluationOrlistat: Teaching, Assessment, and Evaluation


– Limit dietary fat intake.

– Instruct patients to divide daily fat intake equally between meals.


– Orlistat therapy is effective if weight loss occurs without major GI adverse effects or vitamin deficiency occurring.


QuestionQuestion

• Patients prescribed orlistat should be taught to limit their fat intake to ______ of their daily caloric intake.

– A. 5%

– B. 10%

– C. 20%

– D. 30%


AnswerAnswer

• D. 30%

• Rationale: Teach patients to limit dietary fat. Calories from fat should be no more than 30% of daily calories. This percentage promotes weight loss and prevents and minimizes GI adverse effects.


Antiemetics Antiemetics • Nausea and vomiting related to oncologic therapy is

frequently difficult to manage.

• Antiemetics, which suppress stimulation of the CTZ and the VC, are used to treat nausea and vomiting.

• Antiemetic drugs are primarily from three main drug classifications—selective serotonin receptor antagonists, antidopaminergic drugs, and anticholinergic drugs.

• Selective Serotonin Receptor Antagonists

– Prevent the stimulation of type 3 serotonin receptors in the CTZ

• Prototype drug: ondansetron (Zofran)


Ondansetron: Core Drug Knowledge Ondansetron: Core Drug Knowledge


– Prevents nausea and vomiting associated with cancer chemotherapy


– Metabolism: liver. Excreted: kidneys.


– Blocks these receptor sites, thus preventing nausea and vomiting


Ondansetron: Core Drug Knowledge (cont.)Ondansetron: Core Drug Knowledge (cont.)


– Hypersensitivity

• Adverse effects

– Headache, constipation, and malaise


– Drugs metabolized by the cytochrome P-450 enzymes


Ondansetron: Core Patient Variables Ondansetron: Core Patient Variables

• Health status

– Assess symptoms and allergies.



• Environment

– Usually given in acute care settings


Ondansetron: Nursing Diagnoses and Outcomes Ondansetron: Nursing Diagnoses and Outcomes • Imbalanced Nutrition: Less than Body Requirements related to

severe nausea and vomiting

– Desired outcome: Nutritional needs will be met, and ondansetron therapy will prevent severe nausea and vomiting.

• Risk for Altered Comfort related to severe nausea and vomiting

– Desired outcome: Comfort will be maintained, and ondansetron therapy will prevent severe nausea and vomiting.

• Potential Complication: Altered Cardiac Output related to adverse effects of ondansetron

– Desired outcome: Cardiac output will not be affected adversely by possible hypotension and arrhythmias from ondansetron.


Ondansetron: Planning and InterventionsOndansetron: Planning and Interventions


– Administer 30 minutes before chemotherapy.

– Infusions should be given over 15 minutes.


– Dilute in 50 mL of 5% dextrose or 0.9% sodium chloride.

– Do not mix with alkaline solutions.


Ondansetron: Teaching, Assessment, and EvaluationOndansetron: Teaching, Assessment, and Evaluation


– Explain the purpose of the drug.

– Teach patients to change positions slowly to avoid weakness or dizziness.


– Ondansetron therapy is considered effective if nausea and vomiting are controlled and adverse effects are controlled or do not occur.


QuestionQuestion

• Ondansetron should be given

– A. Rapid IV push

– B. IV over 15 minutes

– C. IV over 30 minutes

– D. IV over 1 hour


AnswerAnswer

• B. IV over 15 minutes

• Rationale: Ondansetron should be given IV over 15 minutes.

ppt chapter 36

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