GASTRO-INTESTINAL SYSTEM

  • Mouth: Breaks up food; saliva assists digestion (amylase).
  • Pharynx & Esophagus: Swallowing & transport of food.
  • Liver: Processes molecules; stores vitamins and iron; produces bile.
  • Gallbladder: Stores bile.
  • Stomach: Churns food; activates enzymes (pepsin, HCl); limited nutrient absorption.
  • Small Intestine: Completes digestion; absorbs nutrients and water.
  • Pancreas: Produces hormones, bicarbonates; digests carbohydrates, proteins, and fats.
  • Large Intestine: Reabsorbs water; stores feces.

CONSTIPATION

  • Definition: Hard fecal material accumulation.
  • Causes: Fecal impaction, bowel obstruction, chronic laxative use, neurologic disorders, drugs (narcotics).
  • Laxatives: Drugs to produce soft stool.
  • Cartharsis: Prompt bowel evacuation. Contraindications: Abdominal pain, nausea, cramps, appendicitis.

LAXATIVE CLASSIFICATIONS

  • Bulk Forming: (e.g., Methylcellulose, Psyllium) – increases fecal mass via water absorption.
  • Surfactant: (e.g., Docusate) – softens stool by allowing water to penetrate.
  • Stimulant: (e.g., Bisacodyl, Senna) – promotes peristalsis.
  • Osmotic: (e.g., Magnesium hydroxide) – retains water in intestines.
  • Miscellaneous: (e.g., Mineral oil) – lubricates and reduces water absorption.

DIARRHEA

  • Definition: Excessive, watery stool and increased frequency.
  • Management: Treat underlying cause, replace fluids, relieve cramping.
  • Antidiarrheal Agents: Non-specific (Diphenoxylate, Loperamide) and specific treatments.

EMESIS (VOMITING)

  • Mechanism: Reflex via the vomiting center in the medulla; triggered by various stimuli.
  • **Drugs: Emetic agents (e.g., Syrup of ipecac) contraindicated in certain poisoning.
  • Antiemetics Classes: Serotonin antagonists (ondansetron), dopamine antagonists (Prochlorperazine), anticholinergics (dimenhydrinate).

PEPTIC ULCER DISEASE (PUD)

  • Pathogenesis: Balance disruption between aggressive (HCl, pepsin) and protective factors (mucus, bicarbonate).
  • NSAIDs: Can cause ulcers; management requires cessation and monitoring.
  • Presentation: Symptoms include dyspepsia and epigastric pain.

DRUGS FOR PEPTIC ULCER

  • Classes: Antacids, H2 blockers (e.g., Cimetidine), proton pump inhibitors (PPIs) (e.g., Omeprazole).
  • Mechanism of Action: Vary among classes; mostly inhibit acid secretion.
  • Side Effects: Include confusion, dizziness, diarrhea, and headaches with H2 blockers and PPIs.

DENTIFRICES & MOUTHWASHES

  • Dentifrices: Clean teeth; fluoride reduces decay rates; inclusion of xylitol helps prevent caries.
  • Mouthwashes: Antiseptic solutions enhance dental hygiene; can contain various ingredients (alcohol, chlorhexidine).

XEROSTOMIA (DRY MOUTH)

  • Causes: Blocked saliva flow due to medications or conditions.
  • Management: Increase hydration, use sugar-free gum, monitor electrolyte balance.