GI_Drugs

Gastrointestinal Medications Overview

• Course Title: HSCI 3020

Purpose of the GI System

• Processes food for bodily functioning.

• Also known as:

  • Digestive system

  • GI tract

  • Alimentary tract/canal.

• Involves:

  • Food intake through the mouth.

  • Digestion of food.

  • Expulsion of waste as feces.

Gastrointestinal System Structure

• Upper GI:

  • Oral cavity (mouth)

  • Esophagus

  • Stomach

  • Duodenum (first part of the small intestine)

• Lower GI:

  • Jejunum and ileum (small intestine)

  • Cecum, ascending colon, transverse colon, descending colon, sigmoid colon (large intestine)

  • Rectum

  • Anus

Digestive System Components

• Includes the GI tract and accessory organs of digestion:

  • Tongue

  • Salivary glands

    • Parotid glands

  • Pancreas

  • Liver

  • Gallbladder

Major Activities of the Digestive System

• Secretion:

  • Release of enzymes and other substances.

• Digestion:

  • Breakdown of food.

• Absorption:

  • Absorption of water and nutrients.

• Motility:

  • Movement of food and secretions.

Common Diseases of the GI System

• Gastroesophageal reflux (GERD)

• Peptic ulcers

• Nausea, vomiting, diarrhea (N/V/D)

• Constipation

• Irritable bowel syndrome (IBS)

• Inflammatory bowel disease (Crohn's disease, ulcerative colitis)

• Gastroenteritis

• Diverticular disease

Gastroesophageal Reflux (GERD)

• Definition: Stomach contents move up into the esophagus.

• Treatments include:

  • Antacids (Tums, etc.)

  • Histamine type 2 (H2) antagonists:

    • Block release of histamine, decreasing gastric acid production.

    • Examples: Cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid).

  • Proton pump inhibitors (PPIs):

    • Suppresses gastric acid production.

    • Replaced H2 antagonists.

    • Examples: Omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid).

Peptic Ulcers

• Definition: Hole in the inner lining of the GI tract caused by erosion from acid.

• Treatments include:

  • H2 antagonists and PPIs.

  • Misoprostol:

    • Stimulates mucous production, decreases acid secretion.

    • Used in patients taking NSAIDs; contraindicated in pregnancy.

  • Sucralfate:

    • Forms a protective coating over ulcers.

Antiemetics (for Nausea and Vomiting)

• Reduce nausea and vomiting. Types:

  • Histamine type 1 (H1) antagonists:

    • Examples: Promethazine (Phenergan), diphenhydramine (Benadryl), meclizine (used for sea-sickness).

  • Serotonin (5-HT3) receptor blockers:

    • Example: Ondansetron (Zofran).

  • Metoclopramide (Reglan):

    • Increases GI motility.

  • Herbals:

    • Ginger, peppermint, Vitamin B6.

  • Acupressure wristbands:

    • Sea Bands.

Antidiarrheals

• Antimotility drugs:

  • Slow down GI tract.

  • Examples:

    • Loperamide (Imodium)

    • Pepto Bismol

    • Lomotil

    • Paregoric.

Drugs Used for Constipation

• Stimulants:

  • Irritate the colon and increase motility.

  • Examples: Bisacodyl (Correctol, Doxidan, Dulcolax, Fleets), Senna (Senokot), Castor oil.

• Bulk laxatives:

  • Increase bulk by pulling extra water into stool.

  • Examples: Bran, psyllium (Metamucil).

• Stool softeners and lubricants:

  • Examples: Docusate (Colace), mineral oil, glycerin.

Irritable Bowel Syndrome (IBS)

• Characterized by:

  • Abdominal distress

  • Diarrhea or constipation

  • Bloating, nausea, flatulence

  • Headache, fatigue, depression, anxiety.

• Types:

  • IBS-D: Diarrhea dominant

  • IBS-C: Constipation dominant.

• Treatments:

  • Eluxadoline (Viberzi): Opioid agonist for IBS-D.

  • Lubiprostone (Amitza): Chloride channel activator for IBS-C.

Inflammatory Bowel Disease (IBD)

• Includes:

  • Crohn's disease

  • Ulcerative colitis.

• Treatments will be covered later in the semester.

Gastroenteritis

• Known as:

  • "Stomach bug" or "stomach flu."

• Infectious disease affecting the GI system.

• Most cases are viral; some less common cases are caused by bacteria, parasites, or protozoans.

• Medications will be covered later.

Diverticular Disease

• Definition: Diverticula are small pouches that form in the walls of the colon.

• Causes:

  • Pain, inflammation, and sometimes obstruction.

• Treatments include:

  • Anti-inflammatories and antibiotics if indicated; will cover later.