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Pharmacology of Gastrointestinal Disorders

Overview of Gastrointestinal Drugs

Drugs for Gastrointestinal Disorders

  • Gastrointestinal disorders can include:
    • Peptic Ulcers
    • Heartburn
    • Gastroesophageal Reflux Disease (GERD)
    • Diarrhea
    • Constipation
    • Vomiting
    • Gastroparesis

Structure and Function of the Digestive System

  • Salivary Glands: Provide lubrication, buffers, and enzymes for digestion.
  • Esophagus: Passageway to the stomach.
  • Stomach: Produces acid and enzymes.
  • Small Intestine: Absorbs nutrients.
  • Liver: Produces bile and regulates blood chemistry.
  • Gallbladder: Stores bile.
  • Pancreas: Produces digestive enzymes and buffers, has endocrine functions.
  • Large Intestine: Absorbs water and stores waste.

Peptic Ulcers

  • Definition: Ulcers occurring in the gastrointestinal tract due to acid.
  • Causes:
    • Presence of Helicobacter pylori
    • Long-term use of NSAIDs or aspirin
    • Alcohol, caffeine, and smoking.
  • Symptoms:
    • Abdominal pain (often related to meal timing)
    • Bloating, nausea, vomiting, loss of appetite, weight loss
    • Hematemesis (vomiting blood)
  • Treatment:
    1. Stop NSAIDs,
    2. If H. pylori is present, use Triple Therapy: PPI and two antibiotics.
    3. If no H. pylori, use PPIs or H2 blockers.

Heartburn

  • Description: Burning sensation in the chest often post consumption or while lying down.
  • Causes: Backflow of stomach acid into the esophagus.
  • Prevention Tips:
    • Avoid fatty foods, caffeine, and smoking.
  • Treatment Options:
    • Over-the-counter antacids
    • H2 receptor antagonists
    • Proton pump inhibitors (PPIs).

Antacids

  • Mechanism: Neutralize stomach acidity.
  • Main Ingredients:
    • Magnesium: Causes diarrhea.
    • Calcium: Can cause constipation.
    • Aluminum: Causes constipation; may lead to osteoporosis with excessive use.
  • Important Considerations:
    • Antacids can hinder absorption of certain medications.
    • Timing of administration should be considered to avoid interactions.

GERD (Gastroesophageal Reflux Disease)

  • Definition: Chronic condition where stomach contents return to the esophagus.
  • Symptoms: Heartburn, regurgitation, nausea.
  • Treatment:
    • Antacids (e.g., Gaviscon)
    • Prescription PPIs.

Proton Pump Inhibitors (PPIs)

  • Function: Block the proton pump (H+/K+ ATPase) to reduce gastric acid.
  • Uses: Treat peptic ulcers, GERD, and others.
  • Side Effects: Headache, dizziness, potential long-term health risks (e.g., pneumonia).

Diarrhea Classification**

  • Acute Diarrhea: Lasts < 2 weeks, often caused by infections.
  • Chronic Diarrhea: Lasts > 4 weeks, linked to conditions like IBD.
  • Osmotic: Malabsorption leads to watery stools.
  • Secretory: Excess fluid secretion, often due to infections.
  • Traveler’s Diarrhea: Contracted during travel.

Constipation**

  • Definition: Infrequent or hard-to-pass bowel movements.
  • Common Causes: Low fiber diet, medications (opioids, diuretics), metabolic disorders.
  • Treatment Options:
    • Osmotic Laxatives: Pull water into the intestines.
    • Stool Softeners: Help mix fluids with stool.
    • Stimulant Laxatives: Trigger bowel contractions.

Gastroparesis**

  • Definition: Delayed gastric emptying.
  • Symptoms: Nausea, feeling full quickly, vomiting.org
  • Treatment Options:
    1. Medications: Metoclopramide (for stimulating stomach contractions).
    2. Dietary changes: Smaller, more frequent meals.
    3. Botox injections: Relax pyloric sphincter to improve emptying.

Notes:

  • Addressing GI issues requires a holistic understanding of both medications and lifestyle adjustments.
  • Always consider patient-specific factors such as existing health conditions and potential medication interactions.