GI Disorders and Medications

Unit 6: GI Disorders and Medications

Learning Outcomes

• Describe the homeostatic functions of the gastrointestinal system.
• Summarize the pathophysiology of selected gastrointestinal disorders, and identify their significance to pharmacological treatments.
• Identify the essential components for understanding the pharmacotherapy of prototype drugs for selected gastrointestinal disorders.
• Document pharmacological and non-pharmacological nursing interventions and evaluate the patient’s response.
• List nursing considerations vital in promoting safe administration of selected prototype drugs.
• Identify the nurse’s role in communication and collaboration in the interdisciplinary care of medication administration to patients across the lifespan.
• List the necessary skills to perform medication administration according to best practice.
• Examine professional, legal, and ethical issues related to the pharmacotherapy of a patient with selected gastrointestinal system health problems.

Prototype Drugs

• Omeprazole
• Ranitidine
• Aluminum hydroxide
• Amoxicillin
• Metronidazole
• Tetracycline
• Metoclopramide
• Sucralfate
• Psyllium
• Docusate sodium
• Bisacodyl
• Diphenoxylate with atropine
• Loperamide
• Lubiprostone
• Alosetron
• Sulfasalazine
• Prochlorperazine
• Ondansetron
• Dimenhydrinate
• Scopolamine

Remembering Bowel Segments

• Use the mnemonic "Dow Jones Industrial Averages Closing Stock Report" to remember the order of bowel segments.
• The segments are:
  • Duodenum
  • Jejunum
  • Ileum
  • Appendix
  • Colon
  • Sigmoid
  • Rectum

The Digestive System

• The inner lining includes the mucosa layer.
• Villi and microvilli increase surface area for absorption of food and medications.
• Peristalsis speed should be critical for effective contact and absorption.
  • Too fast can result in insufficient contact and diarrhea.
  • Too slow can lead to constipation or obstructions.
• Digestive enzymes are present in:
  • Salivary glands
  • Stomach
  • Small intestine
  • Pancreas

Acid Production in the Stomach

• The lower esophageal sphincter prevents stomach contents from moving backward.
• The pyloric sphincter regulates the flow of substances leaving the stomach.
• Parietal cells:
  • Secrete 1-3L of hydrochloric acid each day.
  • Break down food and kill ingested microbes.
  • Secrete intrinsic factor for the absorption of vitamin B12.
• Gastric juice has a pH of 1.5-3.5.
  • Natural defenses protect the stomach mucosa.
  • A thick mucus layer and bicarbonate ions are secreted.

Peptic Ulcer Disease (PUD)

• Duodenal ulcers:
  • Occur in the duodenum.
  • Cause gnawing upper abdominal pain.
  • Pain disappears on ingestion of food.
  • Are associated with H. pylori.
• Gastric Ulcers:
  • Occur in the stomach.
  • Cause pain with eating.
  • May result in anorexia, weight loss, or vomiting.
  • Are sometimes related to NSAID use.

Gastroesophageal Reflux Disease (GERD)

• GERD symptoms are caused by weakening of the lower esophageal sphincter (LES).
• When the LES does not close tightly, stomach contents move upward.
• Acid irritates the esophageal mucosa.
• Intense burning (heartburn) and belching may occur.
• Severe GERD can lead to esophagitis, esophageal ulcers, and strictures.
• Lifestyle changes and thorough medication history are important in managing GERD.

Medication Classes for PUD/GERD

• Classes include:
  • Proton Pump Inhibitors
  • H2 Receptor Antagonists
  • Antacids
  • Antibiotics
  • Miscellaneous Drugs

Proton Pump Inhibitors (PPIs)

• Short-term therapy for PUD/GERD.
• Reduce acid secretion in the stomach by binding irreversibly to the "Proton Pump."
  • Activated by food intake.
  • Should be taken 20-30 minutes before the first major meal of the day.
• Heal duodenal ulcers within 4 weeks and gastric ulcers in 6-8 weeks.
• Long-term therapy:
  • May increase the risk for osteoporosis-related fractures.
  • Can interfere with calcium absorption.

Omeprazole (Prilosec)

• Pharmacologic Class: Proton pump inhibitor.
• Actions and Uses:
  • Reduces acid secretion in the stomach by binding irreversibly to the enzyme H+K+-ATPase ("Proton Pump").
  • Used for short-term, 4-8 week therapy of active peptic ulcers (PUD) and GERD.
• Adverse Effects are generally minor and may include:
  • Headache
  • Nausea
  • Diarrhea
  • Rash
  • Abdominal pain
• Nursing Considerations:
  • Administer before breakfast on an empty stomach.
  • Capsules and tablets should not be chewed, divided, or crushed.
• All PPIs end in "-prazole".

H2 Receptor Antagonists

• Histamine has two types of receptors:
  • H1
  • H2
• H1 receptor activation leads to classic symptoms of inflammation and allergy.
• H2 receptor activation increases acid secretion in the stomach.
• H2-receptor antagonists:
  • Suppress the volume and acidity of parietal cell secretions.
  • Duodenal ulcers usually heal in 6-8 weeks.
  • Gastric ulcers may require up to 12 weeks to heal.
• Prototype Drug: Famotidine.

Famotidine (Pepcid)

• Pharmacologic Class: H2-receptor antagonist.
• Actions and Uses: Acts by blocking H2 receptors in the stomach to decrease acid production.
• Adverse Effects
  • Uncommon and mild.
  • May include headache.
• Interactions:
  • Antacids should not be given within 1 hour of famotidine.
  • Smoking may decrease the effectiveness of ranitidine.
• Nursing Considerations: Administer after meals (usually at bedtime).
• All H2-Receptor Antagonists end in "-tidine"

Antacids

• Consist of alkaline, inorganic compounds of aluminum, magnesium, sodium, or calcium.
• Used to neutralize stomach acid.
• Provide temporary relief from heartburn or indigestion.
• Considered safe when taken in doses directed on the labels.
• Act within 10 to 15 minutes
• Duration of action is only 2 hours.
• Prototype Drug: Aluminum Hydroxide

Aluminum Hydroxide

• Pharmacologic Class: Antacid.
• Actions and Uses:
  • Neutralizes stomach acid by raising the pH of the stomach contents.
  • Provides symptomatic relief of heartburn due to PUD or GERD.
• Adverse Effects: Can cause constipation.
• Contraindications: Should not be used in patients with suspected bowel obstruction.
• Nursing Considerations: Administer aluminum antacids at least 2 hours before or after other drugs because absorption could be affected.

Pharmacotherapy of H. Pylori Infection

• H. pylori
  • Adapts by neutralizing high acidity surroundings.
  • Makes adhesins to stick tightly to GI mucosa.
  • 80% of patients with duodenal ulcers.
  • 70% of those with gastric ulcers.
  • Strongly associated with gastric cancer.
• Therapy involves using several antibiotics used to eradicate this bacterium.
  • Increases the effectiveness of therapy
  • Lowers the potential for bacterial resistance.
• Antibiotics are combined with PPI or H2-receptor antagonist.
• It's important to test for H. pylori before initiating treatment for infection!

Combination Antibiotics to Treat H. Pylori

• Commonly used antibiotics:

  • Amoxicillin -Metronidazole
  • Tetracycline

• Actions and Uses: Eradication of H. pylori bacteria

• Adverse Effects: Nausea, Diarrhea.

• Nursing Considerations

  • Advise patient to take amoxicillin, clarithromycin, and metronidazole with food to decrease gastric disturbances.
  • Remind patients to take the full course of prescribed medications.

Remembering Antibiotics Used for H. Pylori Treatment

• Use the mnemonic "Please Make Tummy Better" to remember the typical antibiotic combinations:
  • Proton pump inhibitor
  • Metronidazole
  • Tetracycline
  • Bismuth (Antacid; AKA Pepto-Bismol)

Miscellaneous Drugs (Metoclopramide)

• Metoclopramide (Reglan) is occasionally used for short-term therapy of symptomatic PUD.
  • Indicated in patients who fail to respond to first line drugs. -More commonly prescribed to treat n/v associated with surgery/ chemotherapy -Actions and Uses -Causes muscles in the upper intestine to contract -Resulting in faster emptying of the stomach -Blocks food from reentering the esophagus from the stomach -Adverse Effects -CNS effects -BLACK BOX WARNING: tardive dyskinesia with long term therapy

Complementary and Alternative Therapies: Ginger

• Spice and medicinal herb.
• Stimulates appetite, promotes gastric secretions, increases peristalsis.
• Very successful with nausea.

Sucralfate

• Pharmacologic Class: Mucosal Protectant.

• Actions and Uses:

  • The acidic environment of the stomach and duodenum changes Sucralfate into a protective barrier that adheres to an ulcer.
  • Protects the ulcer from further injury from acid and pepsin.
  • Treats Acute duodenal ulcers.

• Adverse Effects: Not absorbed and has no systemic effects. Can cause constipation.

• Nursing Considerations:

  • To prevent constipation, encourage patients to increase dietary fiber and drink at least 1,500 mL/day if fluids are not restricted.
  • Should be taken four times a day, 1 hour before meals, and again at bedtime for compliance.

• “A Liquid Bandaid”

Nursing Practice Application

• Assessment:
  • Complete health history.
  • Complete drug history.
  • Lifestyle habits.
  • Desired therapeutic effects.
  • Testing for H. pylori if symptoms fail to resolve.
  • Adverse effects.
• Interventions:
  • Encourage appropriate lifestyle changes.
  • Note correlations between discomfort or pain and meals or activities.
  • Continue to monitor for the presence of gastric area pain.
  • It may take several days to weeks to see improvement.
  • If gastric pain continues or worsens after several weeks, notify the provider.

Lower GI Tract: Small Intestine

• Includes the:
  • Duodenum -Jejunum
  • Ileum
• The duodenum receives partially digested food (chyme) from the stomach.

Lower GI Tract: Large Intestine (Colon)

• Function includes the reabsorption of water from waste material.
  • Reabsorption of the proper amount of water results in a normal, soft formed stool.
  • Responsible for excreting remaining fecal material.

Lower GI Tract

• Peristalsis is controlled by the autonomic nervous system.
• Parasympathetic division increases peristalsis.
• Sympathetic division decreases peristalsis.
• Travel time through the entire small intestine varies from 3-6 hours.
• It takes 12-24 hours for waste to journey through the colon.

Constipation

• Defined as a decrease in the frequency of bowel movements causing dry, hard stools that are difficult to evacuate without straining.
• If waste material remains in the colon for an extended period too much water is reabsorbed leading to small hard stools.
• The most severe type is fecal impaction or complete obstruction.
• Normal frequency of bowel movements varies widely.

Laxatives

• Promote evacuation of the bowel.
• Used to prevent and treat constipation.
• It is crucial to rule out bowel obstruction prior to administration.
• Laxatives WILL increase colon pressure and risk bowel perforation in the presence of obstruction.
• Adverse Effects: Abdominal distention and cramping.
• Five Primary Groups
  • Bulk-forming
  • Saline cathartics
  • Stimulant
  • Stool softeners or surfactant
  • Herbal agents

Bulk-Forming Laxatives

• Contain fiber (substance that absorbs water) which increases the size of the fecal mass.
• Considered preferred drugs for chronic constipation.
• May be taken on a regular basis without ill effects.
• Must be taken with plenty of water.
• Have a Slow onset of action.

Saline Cathartics (Osmotic Laxatives)

• Pull water into the fecal mass to create a more watery stool.
• Can produce a bowel movement very quickly.
• Should not be used on a regular basis.
• Can lead to dehydration and electrolyte depletion.

Stimulant Laxatives

• Promote peristalsis by irritating the bowel mucosa.
• Are Rapid acting.
• Are More likely to cause diarrhea/cramping.
• Should be used only occasionally in order to limit laxative dependence/depletion of fluid/electrolytes.

Stool Softeners or Surfactant Laxatives

• Cause more water and fat to be absorbed into the stools.
• Most often used to prevent constipation(after recent surgery).

Herbal Agents

• Natural products
  • Most common: Senna.
• Potent herb that irritates the bowel and increases peristalsis.

Psyllium Mucilloid (Metamucil)

• Therapeutic Class: Bulk-type laxative.
• Actions and Uses:
  • Insoluble fiber that is indigestible and not absorbed from the GI tract.
  • When taken with a sufficient quantity of water, psyllium swells and increases size.
  • Promotes the passage of stool
• Adverse Effects: Rare
  • If taken with insufficient water, may swell in the esophagus and cause an obstruction.
• Contraindications:
  • Undiagnosed abdominal pain
  • Intestinal obstruction
  • Fecal impaction
• Nursing Considerations:
  • Mix with at least 8 oz of water, fruit juice, or milk, and administer immediately.
  • Follow each dose with an additional 8 oz of liquid.
  • Observe older adults closely for possible aspiration.
  • Several doses of psyllium may be needed over 1 to 3 days to produce a therapeutic effect.

Docusate Sodium (Colace)

• Pharmacologic Class: Surfactant Laxatives
• Actions:
  • Lower the surface tension of the stool to allow penetration of water.
• Uses:
  • Treats constipation over time.
  • Prevents painful elimination in patients following a procedure.
• Prevents straining in patients who have conditions such as:
  • Cerebral aneurysm or following MI.
• Decreases the risk of fecal impaction in immobile patients.
• Promote defecation in older adults who have decreased peristalsis due to age-related changes in the Gl tract.

Bisacodyl

• Pharmacologic Class: Stimulant Laxatives
• Actions & Uses Result in stimulation of intestinal peristalsis
• Prepare patient prior to surgery or diagnostic tests, such as colonoscopy.
• Treat short-term constellation associated with high-dose opioid use

Diarrhea

• Increase in the frequency and fluidity of bowel movements.
• Large intestine does not reabsorb enough water from the fecal mass.
• It is a type of body defense meant to eliminate body of toxins/pathogens.
• Prolonged or severe diarrhea can result in significant loss of body fluids and electrolyte disorders.
• Primary Goal: Assess and treat underlying cause.
  • Recent travels, dietary habits, immune system competence, recent drug history

Antidiarrheals

• Choice depends on severity of the condition.

• Assess for any identifiable etiologic factors:

  • Infectious disease, antibiotic/antiparasitic drug.
  • Inflammatory: anti-inflammatory drugs.
  • Adverse effect of pharmacotherapy: Discontinue the offending medication/lower the dose.

• Most Effective= Opioids

• Act directly on the intestine to slow peristalsis. Allow more fluid and electrolyte absorption in large intestine. Cause Central Nervous System depression. -Short-term therapy (Schedule V).

• Other Options: OTC options

Diphenoxylate With Atropine

• Pharmacologic Class: Opioid
• Actions and Uses are to:
  • Slow peristalsis allowing time for additional water reabsorption from colon.
  • Produce more solid stools.
  • Act within 45 to 60 minutes.
  • Atropine = Anticholinergic effects.
• Adverse effects:
  • Very low potential.
  • Dizziness or drowsiness may occur.
• Interactions include:
  • CNS depressants, including alcohol.
• Nursing Considerations
• Should be Schedule V Controlled Substance

Loperamide(Imodium)

• Therapeutic Class: Antidiarrheals

• Actions and Uses -Slows intestinal motility through opioid receptor

  -Direct effects on circular and longitudinal muscle

  -Reduces fecal volume; Increases viscosity

  -NOT a controlled substance; OTC

• Adverse Effects include: -Dizziness, Fatigue, Abdominal pain, Constipation, Nausea

• Nursing Considerations: -Bowel sounds, Stool frequency

  -Should not be used to treat diarrhea caused by poisoning or infection by toxin-producing organisms

Irritable Bowel Syndrome

• Symptoms
  • Abdominal pain, bloating, excessive gas, and colicky cramping. -Bowel habits are altered (diarrhea alternating with constipation)
• Diagnosis
  • Requires that a patient has experienced recurrent abdominal pain or discomfort for at least 3 days per month during the previous 3 months. -- In addition, the patient must also experience two or more of the following symptoms: -Relieved by defecation -Onset associated with a change in stool frequency -Onset associated with a change in stool form or appearance
  • Pharmacotherapy -Targeted at symptomatic treatment -Fiber supplements ease symptoms in some patients and worsen in others -There is no one prototype drug for this condition

Lubiprostone

• Used to treat Irritable Bowel Syndrome with Constipation
• Prototype: Lubiprostone
• Actions and Uses Increases fluid secretion in the intestine to promote intestinal motility
• Used to treat Irritable bowel syndrome with constipation
• Treats Chronic constipation
• Adverse Effects May cause Diarrhea or Nausea in some patients
• Contraindications Do not use in patients with Bowel obstruction
• Nursing Considerations Always Monitor frequency of stools and notify provider if severe diarrhea occurs. Should instruct patients to take the medication with food
• "This medication helps to LUBricate your intestines to promote BM,"

Alosetron

• Used to treat Irritable Bowel Syndrome with Diarrhea
• Actions and Uses
• Selective blockade of 5 HT3 receptors, which innervate the viscera and result in increased firmness in stool and decrease in urgency and frequency of defecation.
• Reserved for the treatment of Female patients who have severe IBS D that has lasted more than 6 months and has been resistant to conventional management.
• Adverse Effects may include:
• Constipation; GI toxicity, such as ischemic colitis, bowel obstruction, impaction, or perforation
• Contraindications:
• Chronic constipation, history of bowel obstruction, Crohn’s disease, ulcerative colitis, impaired intestinal circulation, diverticulitis,
• Nursing Considerations: Because of the potentially fatal outcome of GI toxicity, only patients who meet specific criteria and are willing to sign a treatment agreement may receive prescriptions for the medication. "Instruct patients to watch for rectal bleeding, bloody diarrhea, or abdominal pain and report to the provider. Instruct patients that manifestations should resolve within 1 to 4 weeks but will return 1 week after medication is discontinued."

Inflammatory Bowel Disease

Inflammation of the GI tract
Periods of exacerbations and remissions

• Crohn’s Disease : :: Proximal colon and the terminal ileum ::: Skipped pattern (skipped lesions) Areas of normal bowel between diseased portions
• All layers of the bowel are involved
• Deep ulcerations and classic “cobblestone” look Abscess and peritonitis likely because of bowel perforation Narrowed lumen, ulcerations, scarring fistulas —Ulcerative Colitis
• More localized; Rectum, spreading to cecum
• Inflammation continuous
• Only the mucosal layer is involved
• Prevents absorption of electrolytes and water
• Finger-lik