1. GI system
    The GI system is the only system in the body open to the external environment
  2. Composed of one continuous tube
    • Begins at the mouth
    • Progresses through the esophagus, stomach, and small and large intestines
    • Ends at the anus
  3. Accessory Organs
    • Pancreas
    • Liver
    • Gallbladder
  4. Major Activities of the GI system
    • Secretion: Of enzymes, acid, bicarbonate, and mucus
    • Absorption: Of water and almost all of the essential nutrients needed by the body
    • Digestion: Of food into usable and absorbable component
    • Motility: Movement of food and secretions through the system
  5. Types of Secretions of the GI Tract
    • Saliva
    • Mucus
    • Acid and Digestive Enzymes (Gastin, Pepsin)
    • Secretin
    • Sodium Bicarbonate
    • Pancreatic Enzymes, Other Lipases, and Amylases
    • Bile
    • Endocrine Hormones
  6. Underlying causes of GI disorders
    • Dietary Excess
    • Stress
    • Hiatal Hernia
    • Esophageal Reflux
    • Peptic Ulcer Disease
    • Adverse Drug Effects
  7. Effect of drugs on GI secretions
    • Decrease GI secretory activity
    • Block the action of GI secretions
    • Form protective coverings on the GI lining to prevent erosion from GI secretions
    • Replace missing GI enzymes that the GI tract or ancillary glands and organs can no longer produce
  8. Peptic Ulcers
    • Definition: Erosions in the lining of the stomach and adjacent areas of the GI tract
    • Symptoms: Gnawing, burning pain, often occurring after meals
    • Cause: Bacterial infection by Helicobacter pylori bacteria
  9. Drugs Used in the Treatment of Ulcers
    • Histamine-2 (H2) Antagonists: Block the release of hydrochloric acid in response to gastrin
    • Antacids: Interact with acids at the chemical level to neutralize them
    • Proton Pump Inhibitors: Suppress the secretion of hydrochloric acid into the lumen of the stomach
    • Antipeptic Agents: Coat any injured area in the stomach to prevent further injury from acid
    • Prostaglandins: Inhibit the secretion of gastrin and increase the secretion of the mucous lining of the stomach, providing a buffer
  10. Histamine-2 (H2) Antagonists Actions
    • Selectively block histamine-2 receptor sites
    • This blocking leads to a reduction in gastric acid secretion and reduction in overall pepsin production
    • Cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid), ranitidine (Zantac)
  11. Histamine-2 (H2) Antagonists Indications
    Short-term treatment of active duodenal ulcer or benign gastric ulcer Treatment of pathological hypersecretory conditions such as Zollinger–Ellison syndrome
  12. Histamine-2 (H2) Antagonists Contraindications
    Known allergy
  13. Histamine-2 (H2) Antagonists Cautions
    • Pregnancy or lactation
    • Renal or hepatic dysfunction
  14. Histamine-2 (H2) Antagonists Adverse Effects
    • Prototype: Cimetidine
    • GI effects: diarrhea or constipation
    • CNS effects: headache, dizziness, confusion
    • Cardiac arrhythmias and hypotension
    • Reproductive system – gynecomastia, impotence
  15. Histamine-2 (H2) Antagonists Drug2Drug
    Slows metabolism of warfarin, phenytoin, beta blockers, alcohol, quinidine, lidocaine, theophylline, chloroquine, benzodiazepines, nifedipine, pentoxifylline, tricyclics, procainamide, and carbamazepine
  16. Histamine-2 (H2) Antagonists Nursing Considerations
    • Administer with or before meals and bedtime
    • Monitor cardiac status continually if administering IV
    • Decreased dose in renal/hepatic disease
    • Do NOT administer and antacid and ranitidine together
    • Cimetidine is NOT for < 16 years, nizatidine and ranitidine are NOT for children
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  18. What H2 antagonist has been associated with antiandrongenic effects?
    • Cimitidine
    • Rationale: Cimetidine was the first drug in this class to be developed. It has been associated with antiandrongenic effects, including gynecomastia and galactorrhea.
  19. Antacids Action
    • Neutralize stomach acid by direct chemical reaction
    • sodium bicarbonate (Bell-ans), calcium carbonate (Tums), magnesium salts (MOM), aluminum salts (Amphojel), magaldrate (Riopan)
  20. Antacids Indication
    Symptomatic relief of upset stomach associated with hyperacidity, as well as hyperactivity
  21. Antacids Contraindication
  22. Antacids Cautions
    • Any condition that can be exacerbated by electrolyte imbalance
    • GI obstruction
  23. Antacids Adverse Effects
    • Prototype: Sodium Bicarbonate
    • Monitor acid-base levels and electrolytes
    • Rebound acidity
    • Alkalosis – n/v, h/a, irritability, muscle twitching, coma
    • Hypercalcemia
    • Constipation or diarrhea
    • Hypophosphatemia w/aluminum salts
    • Sodium bicarbonate – fluid retention, heart failure
  24. Antacids Drug2Drug
    Affect the absorption of many other drugs
  25. Antacid Nursing Considerations
    • Administer 1 hour before or 2 hours after other medications
    • Chew tablets thoroughly with glass of water
    • Monitor electrolytes
    • Monitor for diarrhea or constipation
    • Teach acid rebound
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  28. Proton Pump Inhibitor Actions
    • Act at specific secretory surface receptors to prevent the final step of acid production and thereby decrease the level of acid in the stomach
    • omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid), dexlansoprazole (Kapidex), pantoprazole (Protonix), rabeprazole (Aciphex)
  29. Proton Pump Inhibitor Indications
    • Short-term treatment of active duodenal ulcers, GERD, erosive esophagitis, and benign active gastric disease
    • Long-term treatment of pathological hypersecretory conditions
  30. Proton Pump Inhibitor Contraindications
  31. Proton Pump Inhibitor Cautions
    Pregnancy or lactation
  32. Proton Pump Inhibitor Adverse Effects
    • Prototype: Omeprazole
    • CNS effects:
    • Dizziness, headache, asthenia, vertigo, insomnia, apathy
    • GI Effects:
    • Diarrhea, abdominal pain, and tongue atrophy
    • Upper respiratory tract symptoms:
    • Cough, stuff nose, hoarseness, and epistaxis
    • Rash, alopecia, pruritis, dry skin, back pain, and fever
  33. Proton Pump Inhibitor Nursing Considerations
    • Administer before meals
    • Do NOT open, chew, crush capsules
    • Monitor for diarrhea or constipation
    • Teach to eat small frequent meals
    • Medical follow-up after 4- 6 weeks
    • Administer w/ antibiotics for H. pylori
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  35. Antipeptic Agent – GI Protectant Actions
    • Forms an ulcer-adherent complex at duodenal ulcer sites, protecting the sites against acid, pepsin, and bile salts
    • Inhibits pepsin activity to prevent further breakdown
    • sulcralfate (Carafate)
  36. Antipeptic Agent – GI Protectant Indications
    Promote Ulcer Healing
  37. Antipeptic Agent – GI Protectant Contraindications
    • Allergy
    • Renal Failure
  38. Antipeptic Agent – GI Protectant Cautions
    Pregnancy or lactation
  39. Antipeptic Agent – GI Protectant Adverse Effects
    • GI effects:
    • Constipation, diarrhea, nausea, indigestion, gastric discomfort, dry mouth
    • Dizziness, vertigo, sleepiness, skin rash, back pain
  40. Antipeptic Agent – GI Protectan Drug2Drug
    • Aluminum salts
    • Phenytoin, fluoroquinolone, or penicillamine
  41. Antipeptic Agent – GI Protectan Nursing Considerations
    • Administer on empty stomach, 1 hour before or 2 hours after meals and bedtime
    • Monitor for GI pain, constipation
    • Do NOT administer antacids or antibiotics within 30 minutes of sulcralfate
    • Provide frequent oral care
    • Increase fluid & fiber in diet – small, frequent meals
  42. Prostaglandin Actions
    • Inhibits gastric acid secretion and increases
    • bicarbonate and mucous production in the stomach
    • misoprostol (Cytotec) – PGE1
  43. Prostaglandin Contraindications
  44. Prostaglandin Cautions
  45. Prostaglandin Adverse Effects
    • GI effects: Nausea, diarrhea, abdominal pain, flatulence, vomiting, dyspepsia, and constipation
    • GU effects: Miscarriages, excessive bleeding, spotting, cramping, hypermenorrhea, dysmenorrhea, and other menstrual disorders
  46. Prostaglandin Nursing Considerations
    • Administer during NSAID therapy
    • Administer four times/day – w/ meals, bedtime
    • Provide small, frequent meals, increase fluids
    • Pregnancy category X
    • Check pregnancy test w/in 2 weeks of beginning therapy
    • Assess menstrual activity – begin on 2nd or 3rd day of menstrual period
    • Teach to use barrier contraceptives
    • Provide written and oral information on pregnancy risks
    • Teach risks of menstrual disorders and pain, miscarriage risk, excessive bleeding
  47. Digestive Enzyme Supplements
    • Saliva Supplements:
    • Stroke
    • Salivary gland disorder
    • Extreme surgery of the head and neck
    • Pancreatic Enzyme Supplements:
    • Common duct problems
    • Pancreatic disease
    • Cystic fibrosis
  48. Digestive Enzyme Actions
    • Saliva substitute: Contains electrolytes and carboxymethylcellulose to act as a thickening agent in dry mouth conditions
    • Salivart, MouthKote
    • Pancreatic enzymes are replacement
    • enzymes that help the digestion and absorption of fats, proteins, and carbohydrates
    • Pancrelipase (Pancrease, Creon)
    • LactAid for lactose intolerance
  49. Digestive Enzyme Indications
    Replacement Therapy
  50. Digestive Enzymes Contraindications
    • Saliva: Allergy
    • Pancreatic enzymes: Allergy to pork
  51. Digestive Enzyme Cautions
    • Saliva: HF, hypertension, or renal failure
    • Pancreatic enzyme: Pregnancy and lactation
  52. Digestive Enzyme Adverse Effects
    • Prototype: Pancrelipase
    • Saliva substitute: Complications from abnormal electrolytes – increased levels of magnesium, sodium, or potassium
    • Pancreatic enzyme: GI irritation, nausea, abdominal cramps, and diarrhea
  53. Digestive Enzyme Nursing Considerations
    • Swish saliva substitute as needed
    • Administer pancreatic enzymes with meals and snacks
    • Avoid spilling pancreatic enzymes on skin
    • Do NOT crush or chew pancreatic capsule
    • Monitor for electrolyte imbalances
  54. Drugs act in several ways on the secretions of the GI tract. Which action affects the GI secretions least?
    • Replaces secretions
    • Rationale: The effects of drugs on GI secretions- decrease
    • GI secretory activity; block the action of GI secretions; form protective
    • coverings on the GI lining to prevent erosion from GI secretions; replace
    • missing GI enzymes that the GI tract or ancillary glands and organs can no
    • longer produce
Card Set
GI system