Week 7 GI Pharmacology – Columbia University School of Nursing

50 English vocabulary-style flashcards covering key GI pharmacology terms, definitions, mechanisms, adverse effects, and nursing considerations from the Week 7 lecture notes.

Peptic Ulcer Disease (PUD)

Upper-GI ulceration of gastric or duodenal mucosa caused by H. pylori infection or NSAID use plus weakened mucosal defenses.

Helicobacter pylori

Spiral bacterium that colonizes gastric mucosa and is a major triggering factor for PUD; requires combination antibiotic therapy for eradication.

Gastroesophageal Reflux Disease (GERD)

Chronic reflux of stomach acid into esophagus producing heartburn; treated step-wise with antacids, H2 blockers, then PPIs.

H2 Receptor Antagonists (H2 blockers)

Drugs that competitively block histamine-2 receptors on parietal cells to decrease gastric acid secretion.

“-tidine” suffix

Class identifier for H2 blockers such as famotidine, ranitidine, cimetidine.

Proton Pump Inhibitors (PPIs)

Irreversibly inhibit gastric H⁺/K⁺-ATPase to block final step in acid production; most effective antisecretory agents.

“-prazole” suffix

Class identifier for PPIs such as omeprazole, pantoprazole, lansoprazole, esomeprazole.

Talicia

Fixed-dose capsule containing omeprazole + amoxicillin + rifabutin for 14-day eradication of H. pylori.

Sucralfate

Aluminum-salt mucosal protectant that forms viscous barrier over ulcers; give on an empty stomach.

Bismuth subsalicylate (Pepto-Bismol)

Coats ulcers, has mild antimicrobial action; salicylate component requires caution with aspirin allergy.

Antacids

Alkaline compounds taken orally to neutralize existing gastric HCl in lumen and provide rapid symptom relief.

Calcium carbonate

Fast-acting antacid (e.g., Tums) that may cause constipation and hypercalcemia at high doses >10 tablets/day.

Magnesium hydroxide

Potent antacid and osmotic laxative (Milk of Magnesia); common side effect = diarrhea.

Aluminum hydroxide

Antacid often combined with Mg(OH)₂ to balance diarrhea/constipation; can cause constipation and phosphate binding.

Famotidine

Most widely used H2 blocker (Pepcid); OTC for heartburn, Rx dosing for duodenal ulcers.

Ranitidine (Zantac 360)

Re-released ranitidine formulation now containing famotidine after NDMA contamination recall.

Cimetidine

Oldest H2 blocker; numerous CYP450 drug interactions and androgenic side effects.

PPI class side effects

Long-term use: osteoporosis (↓Ca²⁺), ↓Mg/B12/iron, renal injury, C. difficile & pneumonia risk, possible dementia & cardiac issues.

PPI patient teaching

Take 30–60 min before first meal, do not crush delayed-release capsules; lowest effective dose; may sprinkle contents on soft food if instructed.

H2RA class side effects

Can cross BBB → confusion in elderly; rare hepatotoxicity/renal impairment—monitor labs if long-term.

Smoking & H2 blockers

Nicotine increases acid and decreases drug efficacy; advise cessation for optimal benefit.

Bulk-forming laxatives

Fiber agents that swell with water to soften stool and increase mass, promoting peristalsis; prevention, not rapid relief.

Psyllium

Natural soluble fiber (Metamucil) taken with ≥8 oz water; may also lower cholesterol.

Surfactant (stool-softener) laxatives

Lower surface tension allowing water penetration into stool; example docusate sodium.

Docusate sodium

Common stool softener; evidence for efficacy is weak, widely de-implemented in hospitals.

Stimulant laxatives

Directly stimulate intestinal smooth muscle & fluid secretion; bisacodyl, senna; faster but risk dependence.

Senna

Plant-derived stimulant laxative; turns urine/stool brown; chronic use leads to cathartic dependence.

Bisacodyl

Stimulant laxative available PO or suppository (15 min action); enteric coating destroyed by antacids/dairy.

Osmotic laxatives

Non-absorbable salts or polymers that draw water into bowel; high doses for bowel prep.

Polyethylene glycol (PEG)

Iso-osmotic powder; low-dose Miralax for constipation, high-dose GoLytely for colon prep; risk dehydration.

Mineral oil

Lubricant laxative/enema; softens stool but may cause anal leakage and lipid pneumonia if aspirated.

Laxative dependency

Chronic stimulant use diminishes natural defecation reflex, causing need for increasing doses.

Loperamide

Peripherally acting μ-opioid agonist that slows intestinal transit and treats diarrhea; minimal CNS effect at normal dose.

Loperamide dosing limit

2 caps (4 mg) after first loose stool, then 2 mg after each stool; max 8 mg/day OTC to avoid toxicity.

Loperamide & QT prolongation

High doses or with quinine (tonic water) increase risk of fatal ventricular arrhythmias.

Serotonin (5-HT₃) antagonist antiemetics

Block 5-HT₃ receptors in CTZ & GI tract to prevent N/V; prototype ondansetron.

Ondansetron

Gold-standard antiemetic; SE headache, serious risk QT prolongation—monitor ECG with other QT drugs.

Dopamine antagonist / Prokinetic

Metoclopramide blocks D₂ receptors in CTZ and enhances GI motility, useful when nausea + gastroparesis.

Metoclopramide

SE sedation & diarrhea; dangerous long-term effect extrapyramidal symptoms (tardive dyskinesia).

Extrapyramidal symptoms (EPS)

Drug-induced movement disorders such as dystonia, akathisia, Parkinsonism, TD; linked to dopamine blockade.

Tardive dyskinesia (TD)

Irreversible, repetitive involuntary movements after chronic dopamine antagonist exposure (e.g., high-dose metoclopramide).

Promethazine

Antihistamine with antiemetic, sedative, anticholinergic, and α-blocker actions; high-alert for tissue injury IV.

Promethazine IV precaution

Must give via large vein, dilute, and monitor for burning/extravasation to prevent necrosis and gangrene.

Hyoscyamine

Antispasmodic anticholinergic used in IBS; on Beers List due to cognitive & urinary side effects in elders.

Anticholinergic side effects

Dry mouth, blurred vision, tachycardia, urinary retention, constipation, anhidrosis, confusion.

Beers List

Guideline of potentially inappropriate medications for older adults; includes strong anticholinergics & long-term PPIs.

Antacid separation window

Take other oral drugs ≥30–60 min before or after antacids to avoid altered absorption.

PPI nutrient deficiencies

Chronic acid suppression ↓ absorption of Ca²⁺, Mg²⁺, vitamin B₁₂, and iron—monitor levels every 2–3 years.

Antacids & Heart Failure

Many liquid antacids contain sodium; excess Na⁺ can worsen fluid retention in HF patients.

Diarrhea vs Constipation with Antacids

Mg-containing antacids → diarrhea; Al or Ca antacids → constipation; combo products balance effects.