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: Outcomes: soft stool with easier defecation
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

51. Hyperosmotic Laxatives
Glycerine
Action: promotes bowel movement by increasing the osmotic pressure in the intestine.
Note: given in the form of a suppository

52. Stimulant Laxatives
Through the use of natural plant products and synthetic chemical drugs induces intestinal peristalsis.
Note: the stimulant class is the most likely to cause dependence.

53. Stimulant Laxatives Generic: senna Trade: Senokot
Action: stimulates the GI tract
Adverse effects: may cause abdominal pain.
Onset of action: complete bowel evacuation in 6 to 12 hours.

54. Irritable Bowel Syndrome IBS
A condition of chronic intestinal discomfort, including cramps, diarrhea / or constipation.
Two drugs to manage symptoms:
Lotronex (alostron) – approved for women only
Zelnorm (tegaserod) – approved for men and women
Action: works on serotonin receptors in the intestinal tissue.

55. Antiemetic and Antinausea Drugs
Chapter 52

56. Chemoreceptor Trigger Zone (CTZ)
The area of the brain that is involved in the sensation of nausea and the action of vomiting.

57. Vomiting Center (VT)
The area of the brain that is involved in stimulating the physiologic events that lead to nausea and vomiting.

58. Antiemetic Drugs Drugs used to relieve nausea and vomiting.
All emetic drugs work at some site in the vomiting pathways.

59. Syrup of Ipecac
AAP recommendations in 2003 issued an alert to stop the use of this drug to induce vomiting after drug overdose.

60. Anticholinergic Drugs
Act by binding to and blocking acetylcholine receptors (ACh) in the vestibular nuclei, located deep in the brain.
One drug scopolamine
Most commonly used drug for treatment and prevention of nausea and vomiting associated with motion sickness and postoperatively.

61. Antihistamines
Action: binds to H1 receptors, potentiate anticholinergic activity.
Most popular OTC medications
Generic name: dimenhydrinate
Trade name: Dramamine and Benadryl
OTC drugs used for motion sickness

62. Neuroleptics
Action: antidopaminergic, antihistamine and anticholinergic properties.
Trade names: Compazine, Thorazine, Phenergan
Often given as preoperative medication.
Used to treat psychotic disorders due to effect on dopamine.

63. Compazine: Nursing Alert
Adverse reaction: extrapyramidal reaction--a muscle spasm of the tongue. Other typical adverse extrapyramidal reactions include tremors, drooling, and muscle spasms that usually involve muscles in the shoulders, neck, or eyes.
Antidote: Benadryl

64. Prokinetics Metoclopramide Trade name: Reglan
Action: promote the movement of substances through the GI tract and increases motility.
Often given in patients getting tube feeding to promote gastric emptying time.

65. Serotonin Blockers
Called 5-HT3 receptor blockers because they block the 5-HT3 receptors in the GI tract, CTZ and vomiting centers VC.
Four drugs in this category

66. ondansetron Trade name: Zofran is the prototype drug.
Approved in 1992.
Major break through in treating chemotherapy induced nausea and vomiting and postoperative nausea and vomiting.
Approved for use in pregnancy.

67. Side effects from all antiemetics
May cause dizziness
Caution with use while driving.
CNS depression
Hypotension

68. Herbal Therapies Ginger Root
May increase absorption of all oral mediations, may increase bleeding in clients taking Coumadin and Plavix.