Transcript proton pump
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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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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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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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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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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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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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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Types of Acid-Controlling
Drugs
13
Antacids
H2 antagonists
Proton pump inhibitors
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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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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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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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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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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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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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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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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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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
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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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Proton Pump Inhibitors
37
lansoprazole (Prevacid)
omeprazole (Prilosec)
rabeprazole (AcipHex)
pantoprazole (Protonix)
esomeprazole (Nexium)
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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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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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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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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)
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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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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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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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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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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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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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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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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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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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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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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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