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Chapter 50 ACID-CONTROLLING DRUGS DSN KEVIN DOBI, MS, APRN Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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Presentation on theme: "Chapter 50 ACID-CONTROLLING DRUGS DSN KEVIN DOBI, MS, APRN Copyright © 2014 by Mosby, an imprint of Elsevier Inc."— Presentation transcript:

1 Chapter 50 ACID-CONTROLLING DRUGS DSN KEVIN DOBI, MS, APRN Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

2 The stomach secretes:  Hydrochloric acid (HCl)  Bicarbonate  Pepsinogen  Intrinsic factor  Mucus  Prostaglandins Acid-Related Pathophysiology Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 2

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4 Cardiac Pyloric Gastric  The cells of the gastric gland are the largest in number and of primary importance when discussing acid control Glands of the Stomach Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 4

5 Parietal Chief Mucous Endocrine Enterochromaffin Cells of the Gastric Gland Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 5

6 Parietal cells  Produce and secrete HCl  Primary site of action for many of the drugs used to treat acid-related disorders Cells of the Gastric Gland (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 6

7 Parietal Cell Stimulation and Secretion Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 7

8 Chief cells  Secrete pepsinogen, a proenzyme  Pepsinogen becomes pepsin when activated by exposure to acid  Pepsin breaks down proteins (proteolytic) Cells of the Gastric Gland Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 8

9 Mucous cells  Mucus-secreting cells (surface epithelial cells)  Provide a protective mucus coat  Protect against self-digestion by HCl and digestive enzymes Cells of the Gastric Gland (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 9

10 Secreted by parietal cells when stimulated by food, caffeine, chocolate, and alcohol Maintains stomach at pH of 1 to 4 Acidity aids in the proper digestion of food and defenses against microbial infection via the GI tract Secretion also stimulated by:  Large fatty meals  Emotional stress Hydrochloric Acid Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 10

11 Peptic ulcer disease (PUD)  Gastric or duodenal ulcers that involve digestion of the GI mucosa by the enzyme pepsin Helicobacter pylori (H. pylori)  Bacterium found in GI tract of 90% of patients with duodenal ulcers and 70% of those with gastric ulcers  First-line therapy includes a 10- to 14-day course of a proton pump inhibitor and antibiotics Acid-Related Diseases Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 11

12 Stress-related mucosal damage  GI lesions are a common finding in ICU patients, especially within the first 24 hours after admission  Factors include decreased blood flow, mucosal ischemia, hypoperfusion, and reperfusion injury  Nasogastric (NG) tubes and ventilators predispose patients to GI bleeding  A histamine receptor–blocking drug or a proton pump inhibitor are given for prevention Acid-Related Diseases (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 12

13 Antacids H 2 antagonists Proton pump inhibitors Types of Acid-Controlling Drugs Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 13

14 Basic compounds used to neutralize stomach acid Salts of aluminum, magnesium, calcium, and/or sodium Many antacid preparations also contain the antiflatulent (antigas) drug simethicone Antacids Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 14

15 Do not prevent the overproduction of acid but instead help to neutralize acid secretions Promote gastric mucosal defensive mechanisms Stimulate secretion of:  Mucus: protective barrier against HCl  Bicarbonate: helps buffer acidic properties of HCl  Prostaglandins: prevent activation of proton pump Antacids: Mechanism of Action Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 15

16 Reduction of pain associated with acid-related disorders  Raising gastric pH 1 point (1.3 to 2.3) neutralizes 90% of the gastric acid  Reducing acidity reduces pain as a result of:  Base-mediated inhibition of the protein-digesting ability of pepsin  Increase in the resistance of the stomach lining to irritation  Increase in the tone of the cardiac sphincter Antacids: Drug Effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 16

17 Over-the-counter formulations available as:  Capsules and tablets  Powders  Chewable tablets  Suspensions  Effervescent granules and tablets Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 17

18 Used alone or in combination  Aluminum salts  Magnesium salts  Calcium salts  Sodium bicarbonate Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 18

19 Have constipating effects Often used with magnesium to counteract constipation Often recommended for patients with renal disease (more easily excreted) Examples  Aluminum carbonate: Basaljel  Hydroxide salt: AlternaGEL  Combination products (aluminum and magnesium): Gaviscon, Maalox, Mylanta, Di-Gel Antacids: Aluminum Salts Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 19

20 Commonly cause diarrhea; usually used with other drugs to counteract this effect Dangerous when used with renal failure—the failing kidney cannot excrete extra magnesium, resulting in accumulation Antacids: Magnesium Salts Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 20

21 Examples  Hydroxide salt: magnesium hydroxide (Milk of Magnesia)  Carbonate salt: Gaviscon (also a combination product)  Combination products such as Maalox, Mylanta (aluminum and magnesium) Antacids: Magnesium Salts (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 21

22 Many forms, but carbonate is most common May cause constipation, kidney stones Also not recommended for patients with renal disease—may accumulate to toxic levels Long duration of acid action—may cause increased gastric acid secretion (hyperacidity rebound) Often advertised as an extra source of dietary calcium  Example: Tums (calcium carbonate) Antacids: Calcium Salts Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 22

23 Highly soluble Buffers the acidic properties of HCl Quick onset, but short duration May cause metabolic alkalosis Sodium content may cause problems in patients with heart failure, hypertension, or renal insufficiency Antacids: Sodium Bicarbonate Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 23

24 Classroom Response Question Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 24 A patient who has chronic renal failure wants to self- treat with an antacid for occasional heartburn. Which medication is the best choice for this patient? A.A magnesium-containing antacid B.A calcium-containing antacid C.An aluminum-containing antacid D.Because of renal problems, the patient should not take antacids for this problem.

25 Antiflatulents: used to relieve the painful symptoms associated with gas Several drugs are used to bind or alter intestinal gas and are often added to antacid combination products  simethicone Antacids and Antiflatulents Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 25

26 Minimal and depend on the compound used  Aluminum and calcium  Constipation  Magnesium  Diarrhea  Calcium carbonate  Produces gas and belching; often combined with simethicone Antacids: Adverse Effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 26

27 Adsorption of other drugs to antacids  Reduces the ability of the other drug to be absorbed into the body Chelation  Chemical binding, or inactivation, of another drug  Produces insoluble complexes  Result: reduced drug absorption Antacids: Drug Interactions Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 27

28 Increased stomach pH  Increased absorption of basic drugs  Decreased absorption of acidic drugs Increased urinary pH  Increased excretion of acidic drugs  Decreased excretion of basic drugs Antacids: Drug Interactions (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 28

29 Reduce acid secretion All available over the counter in lower dosage forms Most popular drugs for treatment of acid-related disorders  cimetidine (Tagamet)  nizatidine (Axid)  famotidine (Pepcid)  ranitidine (Zantac) Histamine 2 (H 2 ) Receptor Antagonists Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 29

30 Competitively block the H 2 receptor of acid- producing parietal cells Reduced hydrogen ion secretion from the parietal cells Increase in the pH of the stomach Relief of many of the symptoms associated with hyperacidity-related conditions H 2 Antagonists: Mechanism of Action Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 30

31 Drug effect  Suppressed acid secretion in the stomach Indications  Gastroesophageal reflux disease (GERD)  Peptic ulcer disease (PUD)  Erosive esophagitis  Adjunct therapy to control upper GI bleeding  Zollinger-Ellison syndrome H 2 Antagonists: Drug Effect and Indications Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 31

32 Overall, very few adverse effects Central nervous system adverse effects in elderly patients include confusion and disorientation Cimetidine may induce impotence and gynecomastia Thrombocytopenia has been reported with ranitidine and famotidine H 2 Antagonists: Adverse Effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 32

33 cimetidine (Tagamet)  Binds with P-450 microsomal oxidase system in the liver, resulting in inhibited oxidation of many drugs and increased drug levels  All H 2 antagonists may inhibit the absorption of drugs that require an acidic GI environment for absorption H 2 Antagonists: Drug Interactions Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 33

34 Smoking has been shown to decrease the effectiveness of H 2 blockers For optimal results, H 2 receptor antagonists are taken 1 to 2 hours before antacids H 2 Antagonists: Drug Interactions (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 34

35 Classroom Response Question Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 35 When working with an elderly patient who has been admitted for a possible gastrointestinal bleed, the nurse identifies which drug as having the potential to cause confusion and disorientation? A.An antacid B.A proton pump inhibitor C.An H 2 antagonist D.A mucosal protectant

36 The parietal cells release positive hydrogen ions (protons) during HCl production This process is called the proton pump H 2 blockers and antihistamines do not stop the action of this pump Proton Pump Inhibitors (PPIs) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 36

37 lansoprazole (Prevacid) omeprazole (Prilosec) rabeprazole (AcipHex) pantoprazole (Protonix) esomeprazole (Nexium) Proton Pump Inhibitors Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 37

38 Irreversibly bind to H + /K + ATPase enzyme This bond prevents the movement of hydrogen ions from the parietal cell into the stomach Results in achlorhydria—ALL gastric acid secretion is temporarily blocked  To return to normal acid secretion, the parietal cell must synthesize new H + /K + ATPase Proton Pump Inhibitors: Mechanism of Action Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 38

39 GERD Erosive esophagitis Short-term treatment of active duodenal and benign gastric ulcers Zollinger-Ellison syndrome Nonsteroidal antiinflammatory drug (NSAID)– induced ulcers Stress ulcer prophylaxis Treatment of Helicobacter pylori–induced ulcers  Given with an antibiotic Proton Pump Inhibitors: Indications Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 39

40 PPIs are generally well tolerated Possible predisposition to GI tract infections (Clostridium difficile) Osteoporosis and risk of wrist, hip, and spine fractures in long-term users Pneumonia Depletion of magnesium Proton Pump Inhibitors: Adverse Effects Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 40

41 sucralfate (Carafate) misoprostol (Cytotec) simethicone (Mylicon) Miscellaneous Acid-Controlling Drugs Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 41

42 Cytoprotective drug Used for stress ulcers, peptic ulcer disease Attracted to and binds to the base of ulcers and erosions, forming a protective barrier over these areas Protects these areas from pepsin, which normally breaks down proteins (making ulcers worse) Sucralfate (Carafate) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 42

43 Little absorption from the gut May cause constipation, nausea, and dry mouth May impair absorption of other drugs—give other drugs at least 2 hours before sucralfate Do not administer with other medications Binds with phosphate; may be used in chronic renal failure to reduce phosphate levels Sucralfate (Carafate) (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 43

44 Prostaglandin E analog Prostaglandins have cytoprotective activity  Protect gastric mucosa from injury by enhancing local production of mucus or bicarbonate  Promote local cell regeneration  Help to maintain mucosal blood flow Misoprostol (Cytotec) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 44

45 Used for prevention of NSAID-induced gastric ulcers Doses that are therapeutic enough to treat duodenal ulcers often produce abdominal cramps, diarrhea Misoprostol (Cytotec) (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 45

46 Antiflatulent drug Used to reduce the discomforts of gastric or intestinal gas (flatulence) Alters elasticity of mucus-coated gas bubbles, breaking them into smaller ones Result is decreased gas pain and increased expulsion via mouth or rectum Simethicone Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 46

47 Classroom Response Question Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 47 Simethicone (Mylicon) is often combined with calcium carbonate antacids because: A.an increased antacid effect will result when these drugs are given in combination. B.simethicone helps to reduce the gas that is caused by the calcium antacids. C.simethicone reduces the diarrhea that is caused by the calcium. D.simethicone improves the taste of the calcium tablets, which must be chewed.

48 Assess for allergies and preexisting conditions that may restrict the use of antacids, such as:  Fluid imbalances  Renal disease  GI obstruction  Heart failure (HF)  Pregnancy Patients with heart failure or hypertension should not use antacids with high sodium content Nursing Implications: Antacids Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 48

49 Use with caution with other medications because of the many drug interactions Most medications should be administered 1 to 2 hours after an antacid Antacids may cause premature dissolving of enteric-coated medications, resulting in stomach upset Nursing Implications: Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 49

50 Be sure that chewable tablets are chewed thoroughly, and liquid forms are shaken well before giving Administer with at least 8 ounces of water to enhance absorption (except for “rapid-dissolve” forms) Nursing Implications: Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 50

51 Long-term self-medication with antacids may mask symptoms of serious underlying diseases, such as malignancy or bleeding ulcers If symptoms remain ongoing, patient should seek medical evaluation Nursing Implications: Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 51

52 Monitor for adverse effects  Nausea, vomiting, abdominal pain, diarrhea  With calcium-containing products: constipation, acid rebound Monitor for therapeutic response  Notify health care provider if symptoms are not relieved Nursing Implications: Antacids (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 52

53 Assess for allergies and impaired renal or liver function Use with caution in patients who are confused, disoriented, or elderly Take 1 to 2 hours before antacids For intravenous doses, follow administration guidelines Nursing Implications: H 2 Antagonists Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 53

54 Assess for allergies and history of liver disease Not all are available for parenteral administration May increase serum levels of diazepam and phenytoin; may increase chance for bleeding with warfarin Nursing Implications: Proton Pump Inhibitors Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 54

55 The granules of pantoprazole capsules may be given via nasogastric (NG) tubes, but the NG tube must be at least 16 gauge or the tube may become clogged Capsule contents may be opened and mixed with apple juice, but do not chew or crush delayed- release granules Nursing Implications: Proton Pump Inhibitors (cont’d) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 55

56 Classroom Response Question Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 56 When providing education regarding the use of proton pump inhibitors, which statement will the nurse include? A.“Take the medication along with the first meal of the day.” B.“Take the medication on an empty stomach, 30 to 60 minutes before eating.” C.“Take the medication when you have symptoms of heartburn.” D.“Take the medication at bedtime with a snack.”


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