Drugs Affecting the Gastrointestinal System and Nutrition

1. Drugs Affecting the Gastrointestinal System and Nutrition Jan Bazner-Chandler MSN, CNS, RN, CPNP

2. Acid-related Pathophysiology • Hydrochloric acid (HCL) aids in digestion and serves as a barrier to infection. • Pepsinogen is an enzyme that digests dietary protein. • Mucous protects the lining of the stomach from both HCL and digestive enzymes. • Prostaglandins has an anti-inflammatory and protective function.

3. Antacids • Are basic compounds used to neutralize stomach acid.

4. OTC Products • Antacids were the most common products used for acid-indigestion until the 1970’s when histamine-2 (H2 antagonists) were developed.

5. Action • Primary drug effect of antacids is the reduction of symptoms associated with acid-related disorders: pain and reflux (heartburn) • Raises gastric pH from 1.3 to 1.6.

6. Indications • Acute relief of symptoms associated with: • peptic ulcer disease (PUD) • Gastritis • gastric hyperacidity • Heartburn or gastro esophageal reflux (GEF)

7. GERD • Most common disorder of esophagus • Characterized by regurgitation of gastric contents into esophagus and exposure of esophageal mucous to gastric acid and pepsin. • Main symptom is heart burn - occurs after eating • Cause is thought to be incompetent lower esophageal sphincter

8. GERD

9. Peptic Ulcer Disease • Ulcer formation in the esophagus, stomach or duodenum • Mucous exposed to gastric acid and pepsin • Imbalance between cell-destructive and cell-protective effects • Gastric acid and pepsin • H. pylori – infectious process

10. Peptic Ulcer Disease

11. Adverse Effects • Magnesium preparations especially milk of magnesium or MOM can cause diarrhea. • Calcium products can cause kidney stones. • Sodium bicarbonate products can cause systemic alkalosis. • Self-treatment can result in masking symptoms of a disease (bleeding ulcer or stomach cancer).

12. Keep away from small children • Alkalosis

13. Contraindications • Allergy to the drug • Severe renal failure • Electrolyte disturbances • Gastro intestinal obstruction

14. Interaction • May effect absorption of other drugs. • Chemically inactivates certain drugs • Increased stomach pH decreasing absorption of acidic drugs

15. OTC Preparations • Magnesium-containing antacids • Gaviscon Liquid, Milk of Magnesium • Aluminum-containing antacids • Amphogel, Maalox • Sodium-containing antacids • Alka-seltzer, Tums

16. Gelusil / Mylanta

17. Administration • Chewable forms needs to be thoroughly chewed. • Liquid forms need to be shaken well before taking. • Take with 8 ounces of water to enhance absorption. • Do not take within 1 to 2 hours of taking other medications – may effect absorption

18. H 2 Antagonists • H2 receptor blockers • cimetadine (Tagamet), • ranitidine (Zantac) • famotidine (Pepcid) • nizatidine (Axid)

19. H2 antagonist HAs • Action: • blocks the H2 receptor of acid-producing parietal cells • Reduce hydrogen ion secretions to increase pH of stomach

20. Therapeutic Uses • GERD or gastro-esophageal reflux • PUD or peptic ulcer disease • Zollinger-Ellison Syndrome (excessive gastric acidity)

21. Adverse Effects • Overall very low incidence of adverse effects • May cause some CNS effects in the geriatric patient. • Smoking reduces effectiveness • H2 antagonist should be taken 1 hours before taking any antacids

22. Proton Pump Inhibitors • Newest drugs used in the treatment of acid-related disorders. • lansopraxole (Prevacid) • omeprazole (Prilosec) • rabeprzole (Acephex) • pantoprazole (Protonix) • exomepraxole (Nexium)

23. PPIs • Action: Binds directly to the hydrogen-potassium - ATPase pump mechanism, inhibiting the action of the enzyme which results in a total blockage of hydrogen ion secretion from the parietal cells.

24. Adverse Effects • Long term use might promote malignant gastric tumors. • Concern about over prescribing resulting in reduction of normal acid-mediated antimicrobial protection. • May need a probiotic when using PPI drug therapy.

25. Miscellaneous Acid-Controlling Drugs • sucralfate (Carafate) • Uses: long-term therapy for PUD • Action: acts locally binding directly to the surface of the ulcer. • Note: not used as often due to short-term action and multiple daily dosing.

26. Cytotec • Generic: misoprostol • Action: acts on prostaglandin E analogue • Indication: reduces the incidence of gastric ulcers in patients taking NSAIDs.

27. Mylicon • Generic: simethicone • Action: alters the elasticity of mucus-coated gas bubbles, causing them to break down into smaller ones

28. Mylicon • Used to reduce the discomfort of gastric or intestinal gas (flatulence) • Used post-operatively and in post-partum patients to relieve gas pain. • Often used in combination with activated charcoal in oral poisoning (overdose).

29. Probiotics • Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called "friendly bacteria" or "good bacteria." Probiotics are available to consumers mainly in the form of dietary supplements and foods. They can be used as complementary and alternative medicine.

30. Probiotics • Probiotics are available in foods and dietary supplements. Examples of foods containing probiotics are yogurt, fermented and unfermented milk, miso, and some juices and soy beverages. In probiotic foods and supplements, the bacteria may have been present originally or added during preparation.

31. Probiotics • Most probiotics are bacteria similar to those naturally found in people's guts, especially in those of breastfed infants (who have natural protection against many diseases). Most often, the bacteria come from two groups, Lactobacillus or Bifidobacterium. A few common probiotics, such as Saccharomyces boulardii, are yeasts, which are different from bacteria.

32. Uses • Chronic Diarrhea • Irritable Bowel Syndrome • Digestive disorders • Clients on oral or IV antibiotic therapy • Status post abdominal surgery

33. Antidiarrheals and Laxatives Chapter 42

34. Antidiarrheal Drugs • Used to treat diarrhea. • Adsorbents • Antimotility (anticholenergic and opiates) • Intestinal flora modifiers or bacterial replacement drugs

35. Adsorbents • Act by coating the walls of the GI tract. • Bind with the causative bacteria or toxin to their adsorbent surface for elimination through the stool.

36. Pepto-Bismul and Kaoectate • Generic: bismuth subsalicylate • Same chemical structure as salicylate • use with caution in children. May cause Reyes Syndrome • Use with caution in clients who are on anti-coagulation therapy.

37. Pepto-bismol

38. FDA Warning • The main ingredient, bismuth subsalicylate, has been linked with Reye Syndrome, a potentially life-threatening disorder that has been associated with kids that have viral illnesses, especially the flu and chicken pox, and who take aspirin and other salicylate containing medications, like Pepto-Bismol. • Label advises not to give to children under age 12 years.

39. Anticholinergics • Used either alone or in combination with other antidiarrheal drugs. • Acts by slowing GI tract motility • Atropine • hyoscyamine • hyoscine

40. Opiates • Products containing Codeine • Nursing consideration: clients on opioids for post-operative pain control may suffer from constipation. • Atropine: often used to control secretions during surgical procedure – may contribute to post-operative constipation

41. Imodium A D • Generic name: loperamide • Classification: Opiate antidiarrheal • Action: inhibits both peristalsis in the intestine and intestinal secretions, decreasing the number of stools and their water content. • Contraindications: ulcerative colitis, acute diarrhea due to E-coli (Escherichia coli)

42. Laxatives • Laxative act by: • Affecting the consistency of the stool • Increasing fecal movement through the colon • Facilitating movement through the colon

43. Constipation • Definition: abnormally infrequent and difficult passage of feces. • Constipation is a symptom not a disease.

44. Bulk-forming Laxatives • Composed of water-retaining natural and synthetic cellulose derivates. • Psylium is an example of natural bulk-forming laxative. • Methylcellulose is an example of a synthetic cellulose derivative.

45. Bulk-forming Laxative • Action: increases water absorption, which results in greater bulk of the intestinal contents. • Tend to produce normal, formed stools. • Action limited to GI tract so adverse effects are minimal.

46. Citrucel (methylcellulose)

47. Nursing Alert • Have client take with 8 ounces of water. • If powdered form needs to be mixed with 8 ounces of water. • Fluid must be taken immediately to avoid swelling of the product in the throat or esophagus or fecal impaction. • Best for clients with chronic constipation.

48. Emollient laxative • Generic classification: docusate salts • Trade names: Colace, Surfak • Action: work by lowering the surface tension of GI fluids; more water and fat are absorbed into the stool and intestine.

49. Emollients • Uses: • post partum • postoperative patients • Clients on long-term pain control • Outcomes: soft stool with easier defecation

50. Mineral Oil • Action: eases the passage of stool by lubricating the intestines and preventing water from escaping the stool. • Contraindications • Abdominal pain • Nausea and vomiting • Intestinal obstruction