Module 2 GI Medications Flashcards

Peptic Ulcer Disease Overview

• Definition and Characteristics:
  • Peptic ulcers are open sores that develop on the inside lining of the stomach and the upper portion of the small intestine.
  • The most common symptom associated with peptic ulcer disease is stomach pain.
• Classifications of Peptic Ulcers:
  • Gastric Ulcers: Ulcers that occur specifically on the inside lining of the stomach.
  • Duodenal Ulcers: Ulcers that occur on the inside of the upper portion of the small intestine (the duodenum).
• Etiology and Common Causes:
  • Infection caused by the bacterium Helicobacter pylori (H. pylori).
  • Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen sodium.
  • Aggravating Factors vs. Direct Causes: Stress and spicy foods do not cause peptic ulcers directly; however, they can exacerbate and worsen active symptoms.

Histamine Receptor Antagonists

• Representative Medications:
  • Ranitidine
  • Cimetidine
• Drug Interactions and Metabolic Effects of Cimetidine:
  • Cimetidine alters hepatic metabolism of several concomitant medications, leading to elevated serum drug levels and clinical toxicity:
  • Warfarin: Inhibition of warfarin metabolism increases anticoagulant levels, leading to excessive blood thinning and a significant risk of bleeding.
  • Phenytoin: As an anticonvulsant medication, elevated phenytoin concentrations resulting from cimetidine co-administration cause movement problems and slurred speech.

Proton Pump Inhibitors

• Representative Medication:
  • Omeprazole
• Expected Pharmacological Action:
  • Inhibits the gastric parietal cell enzyme system responsible for producing gastric acid, thereby effectively blocking acid production.
• Therapeutic Indications:
  • Short-term therapy for gastric ulcers and duodenal ulcers.
  • Prevention of ulcer formation associated with long-term NSAID therapy.
  • Prophylaxis and prevention of stress ulcers.
• Complications and Nursing Considerations:
  • Administration Timing: Should be administered in the morning prior to eating.
  • Short-Term Use: Generally associated with mild adverse effects.
  • Long-Term Use Complications: Prolonged administration decreases calcium absorption, significantly increasing the risk of osteoporosis and bone fractures.
  • Interventions for Long-Term Risk: Clients taking omeprazole long-term must increase their dietary intake or supplementation of Vitamin D and calcium to mitigate fracture risk.

Mucosal Protectants

• Representative Medication:
  • Sucralfate
• Expected Pharmacological Action and Indication:
  • Prescribed for clients suffering from duodenal ulcers.
  • Upon administration, stomach acid converts sucralfate into a thick, protective barrier that adheres directly to and covers the ulcer bed.
• Drug Interactions and Timing Considerations:
  • Interaction with Other Medications: Sucralfate inhibits the absorption of concurrent medications (such as digoxin and warfarin). A minimum time interval of $2$\,hours must be maintained between the administration of sucralfate and other medications.
  • Interaction with Antacids: Antacids elevate gastric pH and prevent the acid-mediated conversion of sucralfate into its active protective barrier. A minimum time interval of $30$\,minutes must be maintained between antacid administration and sucralfate administration.

Antacids

• Representative Medications:
  • Aluminum Hydroxide
  • Magnesium Hydroxide (Milk of Magnesia / MOM)
  • Calcium Carbonate (Tums)
• Expected Pharmacological Action:
  • Acts as an alkaline base to neutralize gastric acidity.
• Therapeutic Indications:
  • Peptic Ulcer Disease (PUD)
  • Stress-induced gastric ulcers
  • Gastroesophageal Reflux Disease (GERD)
• General Nursing Considerations and Administration:
  • Medication Interference: Antacids interfere with the absorption of a wide variety of medications; co-administration at the exact same time must be avoided.
  • Administration: Administer with a full glass of water.
• Bowel Elimination Complications:
  • Aluminum Hydroxide: Causes constipation.
  • Calcium Carbonate: Causes constipation.
  • Magnesium Hydroxide: Causes diarrhea.
• Electrolyte Imbalances and Contraindications:
  • Aluminum Hydroxide: Can cause low phosphate levels (hypophosphatemia).
  • Calcium Carbonate: Can cause high calcium levels (hypercalcemia).
  • Magnesium Hydroxide: Can cause high magnesium levels (hypermagnesemia). Must be avoided in clients with impaired renal function.

Prostaglandin E Analogs

• Representative Medication:
  • Misoprostol
• Expected Pharmacological Action and Indication:
  • Decreases gastric acid secretion while increasing bicarbonate secretion and protective mucosal lining production in clients undergoing long-term NSAID therapy.
• Safety Warnings and Contraindications:
  • Pregnancy Category: Classified as Pregnancy Category X; must NEVER be taken during pregnancy.
  • Client Education and Warnings: Provide both verbal and written warnings regarding teratogenic hazards.
  • Testing Requirements: Requires a confirmed negative serum (blood) pregnancy test within $2$\,weeks prior to initiating therapy.
  • Contraceptive Adherence: Clients must demonstrate reliable adherence to effective contraceptive measures throughout therapy.
  • Lactation Contraindication: Strictly contraindicated in mothers who are breastfeeding.

Pathophysiology and Etiology of Gastrointestinal Disorders

• Nausea Etiology and Physiology:
  • Physiology: The chemoreceptor trigger zone (CTZ) located within the medulla oblongata receives signals and communicates directly with structures in the vomiting center to initiate the emetic reflex.
  • Common Causes:
  • Pregnancy
  • Systemic or localized infections
  • Metabolic factors, including emotional stress and fear
  • Pharmacological agents, particularly post-operative medications and cancer chemotherapy regimens
• Constipation Etiology:
  • Decreased physical activity
  • Dietary deficiencies
  • Slowed GI motility caused by medications, aging, or specific disease processes
• Diarrhea Etiology:
  • Infectious pathogens (viral or bacterial gastroenteritis)
  • Administration of enteral nutrition formulas
  • Drug therapy, including excessive or routine laxative use
  • Food intolerances, such as lactose intolerance
  • Pathological diseases, including Irritable Bowel Syndrome (IBS) and Crohn's disease

Serotonin Antagonist Antiemetics

• Expected Pharmacological Action:
  • Blocks serotonin receptors that transmit signals from the upper GI tract to the chemoreceptor trigger zone (CTZ).
• Therapeutic Indications:
  • Chemotherapy-induced, radiation-induced, and post-operative nausea and vomiting (should be administered prior to treatment).
  • Pregnancy-induced nausea.
• Complications and Nursing Considerations:
  • Headaches: Treat with non-opioid analgesics.
  • Diarrhea: Monitor frequency and consistency of stools.
  • Cardiac Dysrhythmias: Monitor client cardiac rhythm due to potential dysrhythmias.

Dopamine Antagonist Antiemetics

• Representative Medication:
  • Prochlorperazine
• Expected Pharmacological Action:
  • Blocks dopamine receptors located within the chemoreceptor trigger zone (CTZ).
• Therapeutic Indications:
  • Prevention and management of emesis related to chemotherapy and post-operative status.
• Complications and Nursing Considerations:
  • Extrapyramidal Symptoms (EPS): Manifests as motor restlessness and anxiety; can progress to Tardive Dyskinesia.
  • Interventions: Immediately discontinue the medication, inform the healthcare provider, and administer diphenhydramine as prescribed.
  • Hypotension: Clients should be instructed to change positions and rise slowly to prevent orthostatic falls.
  • Sedation: Avoid activities that require mental alertness, such as operating machinery or driving.
  • Anticholinergic Effects: Manifests as dry mouth, urinary retention, and constipation.
  • Interventions: Administer laxatives or stool softeners as needed, increase physical activity and daily fluid intake, and advise client to suck on hard candy.

Bulk-Forming Laxatives

• Representative Medication:
  • Psyllium
• Expected Pharmacological Action:
  • Consists of non-digestible fiber that absorbs water within the intestinal lumen to form a glutinous mass, adding bulk to the stool.
  • Increasing stool bulk stretches the intestinal wall, stimulating peristalsis while softening and enlarging the fecal mass (action mimics dietary fiber).
• Therapeutic Indications:
  • Temporary treatment of constipation.
  • Management to decrease diarrhea in clients with diverticulosis and Irritable Bowel Syndrome (IBS).
  • Bowel control and regulation for clients with an ileostomy or colostomy.
• Complications and Nursing Considerations:
  • Gastrointestinal Obstruction: Can cause mechanical obstruction of the esophagus or intestines if taken with insufficient fluid. Avoid use in clients with structural narrowing of the GI tract.
  • Administration: Mix with a full glass of water or juice. Ensure the powder is thoroughly dissolved and drink immediately; do not allow the liquid to sit, as it thickens rapidly into a gelatinous mass.

Surfactant Laxatives

• Representative Medication:
  • Docusate Sodium
• Expected Pharmacological Action:
  • Lowers the surface tension of the stool, permitting water penetration and softening the fecal mass for easier passage.
• Therapeutic Indications:
  • Constipation management.
  • Treatment and prevention of fecal impaction.
• Complications and Nursing Considerations:
  • Chronic Use Dangers: Chronic laxative administration leads to severe fluid and electrolyte imbalances and persistent diarrhea.
  • Usage Guidelines: Use occasionally as needed; avoid routine or daily administration.
  • Non-Pharmacological Measures: Attempt conservative non-pharmacological interventions first (such as dietary modification and increased physical activity).
  • Administration: Always take with adequate fluids.

Stimulant Laxatives

• Representative Medications:
  • Bisacodyl
  • Senna
• Expected Pharmacological Action:
  • Directly stimulates intestinal peristalsis.
  • Decreases the absorption of fluid through the intestinal wall, thereby increasing the overall volume of water and electrolytes inside the intestinal lumen.
• Therapeutic Indications:
  • Bowel preparation prior to surgical procedures or diagnostic examinations (such as a colonoscopy).
  • Short-term management of constipation resulting from opioid therapy or slow intestinal transit time.
• Complications and Nursing Considerations:
  • Suppository Risks: Suppositories should not be used on a regular basis; chronic use leads to sluggish bowel function requiring progressively higher doses. Suppositories are typically effective within $1$\,hour.
  • Contraindications: Do not administer to clients with a bowel obstruction.
  • Timing and Drug Interactions: Administer bisacodyl at least $1$\,hour apart from milk or antacids, as alkaline substances dissolve its protective enteric coating prematurely.
  • Onset: Administer oral doses at bedtime to produce bowel movements within $6$ to $12$\,hours.

Osmotic Laxatives

• Representative Medication:
  • Lactulose
• Expected Pharmacological Action:
  • Draws fluid into the intestinal lumen via osmotic pressure, increasing stool mass, stretching the intestinal musculature, and triggering peristalsis.
• Therapeutic Indications:
  • Low-dose therapy for clients requiring painful elimination prevention (such as those with hemorrhoids).
  • High-dose therapy for rapid bowel evacuation prior to a colonoscopy.
• Complications and Nursing Considerations:
  • Dehydration: Monitor closely for dehydration signs. Advise clients to maintain fluid intake of at least $8$ to $10$\,glasses of water per day.

Prokinetic Agents

• Representative Medication:
  • Metoclopramide
• Expected Pharmacological Action:
  • Enhances upper GI tract motility (stomach and intestines) by accelerating peristalsis. Also increases muscle tone in the lower esophageal sphincter.
• Therapeutic Indications:
  • Management of post-operative and chemotherapy-induced nausea and vomiting.
  • Facilitation of small bowel intubation and radiological examination.
  • Management of diabetic gastroparesis and paralytic ileus (contraindicated in mechanical intestinal obstruction).
  • Treatment and management of Gastroesophageal Reflux Disease (GERD).
• Complications and Nursing Considerations:
  • Diarrhea: Monitor for diarrhea and evaluate the client for potential dehydration.

Antidiarrheals

• Representative Medication:
  • Loperamide
• Expected Pharmacological Action:
  • Activates opioid receptors within the GI tract, decreasing intestinal motility and increasing the mucosal absorption of fluid and sodium.
• Therapeutic Indications:
  • Diarrhea management (reduces stool frequency and fluid volume).
• Complications and Nursing Considerations:
  • Fluid Intake: Encourage intake of fluids; avoid relying solely on plain water, as it lacks the electrolytes lost during diarrhea.
  • Dosing Protocol: Dosing may be adjusted according to the number of loose stools passed.
  • Dietary Restrictions: Instruct client to avoid caffeine due to its diuretic properties and its ability to stimulate GI motility.

Probiotics

• Characteristics and Sources:
  • Used to support gastrointestinal microbial balance.
  • Common dietary source includes yogurt.