123 Unit 7: Gastrointestinal Agents

• Fundus


  Main body of the stomach
• Pylorus


  Constricted area leading into the intestine
• Stomach lining (empty)


  • Covered with a layer of mucus which is neutral or alkaline in reaction
• Stomach lining (stimulated by mechanical irritation)

  • Membrane becomes bright red, colorless juice is produced by digestive/gastric/small glands - acidic
• Digestive/Small Glands


  • Parietal Cells: secretes HCl
  • Chief Cells: produces PEPSIN and other enzymes
  • Mucous Cells: secretes MUCIN
• Gastric Juice


  Light colored, thin fluid, acidic, contains enzyme PEPSIN, RENNIN, LIPASE
• Gastric Acidity


  Gastric juice is acidic due to HCl produced by parietal cells, normal pH is 1.6-1.8
• Hyperacidity


  pH is greater than normal
• Hypoacidity


  pH is lower than normal, common in cancer and pernicious anemia
• Achlorhydria


  Absence of HCl in the gastric secretion
• Achlorhydria


  • Mild diarrhoea, Epigastric pain, sensitivity to spicy food, lack of pepsin activity below pH 3.5
• Esophageal Ulcers


  Esophageal sphincter is defective, occurs less in patients with curvature stomach, not always hyperacidity
• Esophageal Ulcers


  • Heartburn, decreased tissue resistance to pepsin, people who contain his/her emotions
• Gastric Ulcers


  More common, chronic condition with scar tissue and potential transformation to malignant
• Gastric Ulcers


  • Diet: inhibit gastric stimulants, Antacid/anticholinergic therapy, After surgery: complete bed rest, Food intake: smaller amount but often
• Antacid Therapy


  Alkaline bases neutralize excess gastric HCl, inactivate pepsin
• Antacid Therapy


  • Administered on continuous basis, can result in acid rebound, side effects: rebound acidity, systemic alkalosis, constipation
• Antacids


  • Sodium Bicarbonate
  • Aluminum-containing: Aluminum Hydroxide, Aluminum Phosphate
  • Calcium-containing: Calcium Carbonate
  • Magnesium-containing: Magnesium Hydroxide, Magnesium Trisilicate
  • Combination Antacid Preparations
  • Simethicone-Containing
  • Calcium-Containing Mixtures
  • Alginic-Acid Sodium Bicarbonate Containing
• Diarrhoea


  Rapid transit of gastric contents through the bowel, loss of balance on the absorption and secretion of water and electrolytes
• Types of Diarrhoea


  • Osmotic: excessive osmotically active particles in the lumen
  • Secretory: bowel mucosa secretes excessive fluid
• Acute Diarrhoea


  • Managed by assessment of fluid balance and rehydration, oral rehydration solutions are effective
• Chronic Diarrhoea


  • Requires careful history, specific investigation and management in secondary or tertiary care
• Antidiarrheal Agents


  Only treat the symptoms and occasionally the cause, but not the complications
• Ideal Antidiarrheal Agent


  • Acts directly on the smooth muscles of the gut to decrease peristalsis and increase segmentation, adsorbent-protective supposedly adsorb toxins, bacteria and viruses and provide a protective coating
• Antidiarrheal Agents


  • Bismuth-containing: Bismuth subnitrate, Milk of Bismuth
  • Activated Clays and other adsorbents: Kaolin, Attapulgite, Activated charcoal
• Constipation


  Uncomfortable or infrequent bowel movements, hard, dry stools due to too much water absorption by the colon
• Constipation


  • Difficult and painful bowel movements, fewer than three times a week, feeling bloated or uncomfortable, feeling sluggish, abdominal pain
• Cathartics (Laxatives/Purgatives)


  Agents that quicken and increase evacuation of bowels, to relieve acute constipation, ease defecation in painful conditions, remove solid material from intestinal tract
• Types of Laxatives


  • Stimulant: Phenolphthalein, Aloin, Cascara, Senna, Castor oil
  • Bulk-forming: Psyllium, Methylcellulose, Carboxymethylcellulose, Karaya gum
  • Emollient: Mineral oil, Docusate
  • Saline cathartics: Biphosphates, Sulfates, Tartrate
• Topical Agents


  Medication applied to the skin or mucous membranes to enter the body, can be for local treatment or to affect the whole body
• Topical agents


  Applying medication to the skin or mucous membranes allows it to enter the body from there
• Topical medication


  • Can be used to treat pain or other problems in specific parts of the body
  • Can be used to nourish the skin and protect it from harm
  • Some are used for local treatment, and some are meant to affect the whole body after being absorbed through the skin
• The skin


  The body's largest and primary protective organ
• Functions of the skin

  • Protection against microorganisms, dehydration, ultraviolet light, and mechanical damage
  • Sensation of pain, temperature, touch, and deep pressure
  • Mobility
  • Endocrine activity (Vitamin D production)
  • Exocrine activity (release of water, urea, ammonia, sebum, sweat, pheromones)
  • Immunity development against pathogens
  • Regulation of temperature
• Topical protectants


  Mild astringents used to treat and prevent various skin conditions including burns, diaper rash, insect bites, and minor skin irritations
• Antimicrobials


  Chemical substances that, directly applied to the skin, inhibit the growth or destroy any microorganism, either fungi, viruses or bacteria
• Types of antimicrobials


  • Antiseptics (directly applied to a living organism to eradicate existing microorganisms)
  • Antibiotics (produced by living organisms or manufactured through synthesis, mainly used to fight infections)
• Protein precipitants


  Chemical substances that cause the precipitation of proteins
• Astringents


  Substances that cause the contraction or shrinkage of tissues and that dry up secretions
• Teeth


  Accessory digestive organs used for biting and chewing