1. Acid-Controlling Drugs DSN Kevin dobi, MS, Aprn
Chapter 50
Acid-Controlling Drugs
DSN Kevin dobi, MS, Aprn
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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

4. Glands of the Stomach Cardiac Pyloric Gastric
The cells of the gastric gland are the largest in number and of primary importance when discussing acid control
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5. Cells of the Gastric Gland
Parietal
Chief
Mucous
Endocrine
Enterochromaffin
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6. Cells of the Gastric Gland (cont’d)
Parietal cells
Produce and secrete HCl
Primary site of action for many of the drugs used to treat acid-related disorders
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7. Parietal Cell Stimulation and Secretion
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8. Cells of the Gastric Gland
Chief cells
Secrete pepsinogen, a proenzyme
Pepsinogen becomes pepsin when activated by exposure to acid
Pepsin breaks down proteins (proteolytic)
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9. Cells of the Gastric Gland (cont’d)
Mucous cells
Mucus-secreting cells (surface epithelial cells)
Provide a protective mucus coat
Protect against self-digestion by HCl and digestive enzymes
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10. Hydrochloric Acid
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
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11. Acid-Related Diseases
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
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12. Acid-Related Diseases (cont’d)
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
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13. Types of Acid-Controlling Drugs
Antacids
H2 antagonists
Proton pump inhibitors
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14. Antacids 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
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15. Antacids: Mechanism of Action
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
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16. Antacids: Drug Effects
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
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17. Antacids (cont’d) Over-the-counter formulations available as:
Capsules and tablets
Powders
Chewable tablets
Suspensions
Effervescent granules and tablets
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18. Antacids (cont’d) Used alone or in combination Aluminum salts
Magnesium salts
Calcium salts
Sodium bicarbonate
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19. Antacids: Aluminum Salts
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
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20. Antacids: Magnesium Salts
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
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21. Antacids: Magnesium Salts (cont’d)
Examples
Hydroxide salt: magnesium hydroxide (Milk of Magnesia)
Carbonate salt: Gaviscon (also a combination product)
Combination products such as Maalox, Mylanta (aluminum and magnesium)
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22. Antacids: Calcium Salts
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)
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23. Antacids: Sodium Bicarbonate
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
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24. Classroom Response Question
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 magnesium-containing antacid
A calcium-containing antacid
An aluminum-containing antacid
Because of renal problems, the patient should not take antacids for this problem.
Correct answer: C
Rationale: Aluminum- and sodium-based antacids are recommended for patients with renal compromise because they are more easily excreted. Both calcium- and magnesium-based antacids are more likely to accumulate to toxic levels in patients with renal disease and are often avoided in this patient group.
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25. Antacids and Antiflatulents
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
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26. Antacids: Adverse Effects
Minimal and depend on the compound used
Aluminum and calcium
Constipation
Magnesium
Diarrhea
Calcium carbonate
Produces gas and belching; often combined with simethicone
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27. Antacids: Drug Interactions
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
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28. Antacids: Drug Interactions (cont’d)
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
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29. Histamine 2 (H2) Receptor Antagonists
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)
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30. H2 Antagonists: Mechanism of Action
Competitively block the H2 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
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31. H2 Antagonists: Drug Effect and Indications
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
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32. H2 Antagonists: Adverse Effects
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
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33. H2 Antagonists: Drug Interactions
cimetidine (Tagamet)
Binds with P-450 microsomal oxidase system in the liver, resulting in inhibited oxidation of many drugs and increased drug levels
All H2 antagonists may inhibit the absorption of drugs that require an acidic GI environment for absorption
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34. H2 Antagonists: Drug Interactions (cont’d)
Smoking has been shown to decrease the effectiveness of H2 blockers
For optimal results, H2 receptor antagonists are taken 1 to 2 hours before antacids
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35. Classroom Response Question
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?
An antacid
A proton pump inhibitor
An H2 antagonist
A mucosal protectant
Correct answer: C
Rationale: H2 antagonists may cause confusion and disorientation in the elderly.
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

36. Proton Pump Inhibitors (PPIs)
The parietal cells release positive hydrogen ions (protons) during HCl production
This process is called the proton pump
H2 blockers and antihistamines do not stop the action of this pump
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37. Proton Pump Inhibitors
lansoprazole (Prevacid)
omeprazole (Prilosec)
rabeprazole (AcipHex)
pantoprazole (Protonix)
esomeprazole (Nexium)
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38. Proton Pump Inhibitors: Mechanism of Action
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
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39. Proton Pump Inhibitors: Indications
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
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40. Proton Pump Inhibitors: Adverse Effects
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
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41. Miscellaneous Acid-Controlling Drugs
sucralfate (Carafate)
misoprostol (Cytotec)
simethicone (Mylicon)
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42. Sucralfate (Carafate)
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)
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43. Sucralfate (Carafate) (cont’d)
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
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44. Misoprostol (Cytotec)
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
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45. Misoprostol (Cytotec) (cont’d)
Used for prevention of NSAID-induced gastric ulcers
Doses that are therapeutic enough to treat duodenal ulcers often produce abdominal cramps, diarrhea
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46. Simethicone 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
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47. Classroom Response Question
Simethicone (Mylicon) is often combined with calcium carbonate antacids because:
an increased antacid effect will result when these drugs are given in combination.
simethicone helps to reduce the gas that is caused by the calcium antacids.
simethicone reduces the diarrhea that is caused by the calcium.
simethicone improves the taste of the calcium tablets, which must be chewed.
Correct answer: B
Rationale: Calcium carbonate neutralization will produce gas and possibly belching, so the addition of simethicone is intended to reduce this effect. Simethicone alters elasticity of mucus-coated gas bubbles, breaking them into smaller ones, resulting in decreased gas pain and increased expulsion via mouth or rectum.
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Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

48. Nursing Implications: Antacids
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
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49. Nursing Implications: Antacids (cont’d)
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
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50. Nursing Implications: Antacids (cont’d)
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)
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51. Nursing Implications: Antacids (cont’d)
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
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52. Nursing Implications: Antacids (cont’d)
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
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53. Nursing Implications: H2 Antagonists
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
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54. Nursing Implications: Proton Pump Inhibitors
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
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55. Nursing Implications: Proton Pump Inhibitors (cont’d)
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
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56. Classroom Response Question
When providing education regarding the use of proton pump inhibitors, which statement will the nurse include?
“Take the medication along with the first meal of the day.”
“Take the medication on an empty stomach, 30 to 60 minutes before eating.”
“Take the medication when you have symptoms of heartburn.”
“Take the medication at bedtime with a snack.”
Correct answer: B
Rationale: Food may decrease absorption of the proton pump inhibitors, and it is recommended that they be taken on an empty stomach. They are taken on a daily basis, not as needed for heartburn.
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.