proton pump

Report
Chapter 50
ACID-CONTROLLING DRUGS
DSN
Copyright © 2014 by Mosby, an imprint of Elsevier
Inc.
KEVIN DOBI, MS, APRN
Acid-Related Pathophysiology
2
 The stomach secretes:
 Hydrochloric acid (HCl)
 Bicarbonate
 Pepsinogen
 Intrinsic factor
 Mucus
 Prostaglandins
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3
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Inc.
Glands of the
Stomach
4
 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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Inc.
Cells of the Gastric
Gland
5
 Parietal
 Chief
 Mucous
 Endocrine
 Enterochromaffin
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Cells of the Gastric
Gland (cont’d)
6
 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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Inc.
Parietal Cell Stimulation and Secretion
7
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Cells of the Gastric
Gland
8
 Chief cells
 Secrete pepsinogen, a proenzyme
 Pepsinogen becomes pepsin when activated by
exposure to acid
 Pepsin breaks down proteins (proteolytic)
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Cells of the Gastric
Gland (cont’d)
9
 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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Inc.
Hydrochloric
Acid
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

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Inc.
Acid-Related
Diseases
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
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Inc.
Acid-Related Diseases
(cont’d)
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
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Inc.
Types of Acid-Controlling
Drugs
13
 Antacids
 H2 antagonists
 Proton pump inhibitors
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Inc.
Antacids
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
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Inc.
Antacids: Mechanism
of Action
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

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Antacids: Drug
Effects
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

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Antacids17 (cont’d)
 Over-the-counter formulations available as:
 Capsules and tablets
 Powders
 Chewable tablets
 Suspensions
 Effervescent granules and tablets
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Antacids18 (cont’d)
 Used alone or in combination
 Aluminum salts
 Magnesium salts
 Calcium salts
 Sodium bicarbonate
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Antacids: Aluminum
Salts
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

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Antacids: Magnesium
Salts
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
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Inc.
Antacids: Magnesium
Salts (cont’d)
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)
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Inc.
Antacids: Calcium
Salts
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)
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Antacids: Sodium
Bicarbonate
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
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Inc.
Classroom Response Question
24
A patient who has chronic renal failure wants to selftreat 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.
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Inc.
Antacids and 25Antiflatulents
 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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Inc.
Antacids: Adverse
Effects
26
 Minimal and depend on the compound used
 Aluminum and calcium


Magnesium


Constipation
Diarrhea
Calcium carbonate

Produces gas and belching; often combined with simethicone
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Inc.
Antacids: Drug
27 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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Inc.
Antacids: Drug Interactions
(cont’d)
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
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Histamine 2 (H2) Receptor
Antagonists
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)

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H2 Antagonists:
Mechanism
30 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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H2 Antagonists: Drug Effect
and Indications
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
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H2 Antagonists:32Adverse 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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H2 Antagonists: Drug
Interactions
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 H2 antagonists may inhibit the absorption of drugs
that require an acidic GI environment for absorption
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H2 Antagonists: Drug34 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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Classroom Response Question
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 H2 antagonist
D. A mucosal protectant
Copyright © 2014 by Mosby, an imprint of Elsevier
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Proton Pump Inhibitors
(PPIs)
36
 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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Inc.
Proton Pump Inhibitors
37
 lansoprazole (Prevacid)
 omeprazole (Prilosec)
 rabeprazole (AcipHex)
 pantoprazole (Protonix)
 esomeprazole (Nexium)
Copyright © 2014 by Mosby, an imprint of Elsevier
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Proton Pump Inhibitors:
Mechanism
38 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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Inc.
Proton Pump Inhibitors:
Indications
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
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Inc.
Proton Pump Inhibitors:
Adverse40 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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Miscellaneous Acid-Controlling
Drugs
41
 sucralfate (Carafate)
 misoprostol (Cytotec)
 simethicone (Mylicon)
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Inc.
Sucralfate42(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)
Copyright © 2014 by Mosby, an imprint of Elsevier
Inc.
Sucralfate (Carafate)
(cont’d)
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
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Inc.
Misoprostol
44 (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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Misoprostol (Cytotec)
(cont’d)
45
 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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Inc.
Simethicone
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
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Inc.
Classroom Response Question
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.
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Inc.
Nursing Implications:
Antacids
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
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Inc.
Nursing Implications:
Antacids (cont’d)
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
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Inc.
Nursing Implications:
Antacids (cont’d)
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)
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Inc.
Nursing Implications:
Antacids (cont’d)
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
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Inc.
Nursing Implications:
Antacids (cont’d)
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
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Nursing Implications:
H2 Antagonists
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
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Inc.
Nursing Implications: Proton Pump
Inhibitors
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
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Inc.
Nursing Implications: Proton Pump
Inhibitors
55 (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 delayedrelease granules
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Classroom Response Question
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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Inc.

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