Gastrointestinal Drugs

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Pharmacology I: NURS 1950
1
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Objective 1: list the components of gastric
juice that contribute to the pain associated
with peptic ulcers
Objective 2: describe the physiology of
gastric secretions
2
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Objective 3: list drugs considered to be
ulcerogenic
3
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Objective 4: explain the actions of the
antiulcer drugs
◦ Decrease acidity
◦ Block histamine receptors
◦ Gastrointestinal prostaglandins
4
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Gastric acid pump inhibitors
Coating agents
Prokinetic agents
Antispasmodic agents
5
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Objective 5: describe the pain reducing
effects of antacids
6
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Raise the pH of gastric contents
◦ Higher pH, less acidity
 Decreased pain
7
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Objective 6: identify the features of an ideal
antacid
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◦
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Cheap
Effective
No constipation or diarrhea
No systemic effects
No rebound acidity
8
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Objective 7: differentiate between the various
antacids
9
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Riopan, Maalox, Mylanta II, low sodium
Calcium carbonate, Aluminum hydroxide:
constipation
Magnesium: diarrhea, electrolyte imbalance
Calcium carbonate & sodium bicarbonate:
rebound acidity
10
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Simethicone: defoaming agent
Alginic acid: highly viscous solution—sodium
alginate
11
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Objective 8: describe the nursing implications
associated with antacid therapy
12
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What are the assessments and interventions
the nurse would do for a client taking an
antacid?
13
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Objective 9: state the mechanism of action of
anticholinergic and antispasmodic agents
14
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Anticholinergics and antispasmodics the
same
◦ Drugs include belladonna, probanthine, bentyl
◦ Used for spastic conditions of GI tract, peptic
ulcers and irritable bowel syndrome
◦ Block parasympathetic nervous system
 Activity is systemic
 What would you see with
anticholinergics?
15
◦ Which clients should not use anticholinergics?
16
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Objective 10: identify appropriate nursing
actions relative to caring for clients receiving
antispasmodic drugs
17
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Assess: mental status, teach about
orthostatic hypotension
In the elderly: increased constipation
If arrhythmia or palpitations: stop the drug,
call the physician
18
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Objective 11: describe the effects and uses
of H2 receptor antagonists, and proton
pump inhibitors
19
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H2 receptor antagonists
◦ Block histamine 2 receptors
◦ Raises pH of gastric contents
 Used for GERD, duodenal ulcers,
Zollinger-Ellison syndrome
 Used to prevent or treat stress ulcers
20
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Drugs include
◦
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◦
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Cimetidine (Tagamet)
Famotidine (Pepcid)
Nizatidine (Axid)
Rantidine (Zantac)
21
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Drugs can cause
◦ Dizziness, HA, diarrhea, constipation
◦ If confusion, disorientation, hallucination, see MD
◦ Can cause gynecomastia, hepatotoxicity
22
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Proton pump inhibitors
◦ Inhibit gastric acid pump
◦ Treat: severe esophagitis, GERD, gastric and
duodenal ulcers, Zollinger-Ellison syndrome
◦ Can be used with antibiotics for H pylori
23
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SE: diarrhea, HA, muscle pain and fatigue
If rash: call MD
24
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Drugs include
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Esomeprazole (Nexium)
Lansoprazole (Prevacid)
Omeprazole (Prilosec)
Pantoprazole (Protonix)
Rabeprazole (Aciphex)
25
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Objective 12: Explain the nursing
interventions associated with H2 receptor
antagonists and proton pump inhibitors
26
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Objective 13: identify causes of constipation
Objective 14: explain the uses of laxatives
and cathartics
Objective 16: describe the actions of the
types of laxatives
Objective 17: identify laxatives according to
type
27
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Causes of constipation
◦ What are some things or conditions that can cause
constipation?
28
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Act three ways
◦ Affect fecal consistency
◦ Increase fecal movement
◦ Remove stool from rectum
29
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Laxatives OTC; misused
◦ Dependence
◦ Damage bowel
◦ Cause problems in bowel
30
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Caution: surgical abdomen; appendicitis;
N/V; fecal impaction; intestinal obstruction;
undiagnosed abdominal pain
Contraindicated: hypersensitivity
31
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Bulk-forming
Emollient
Hyperosmotic
Saline
Stimulant
32
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Bulk-forming: natural fiber-like
◦ Absorb water
◦ Distends bowel
◦ Initiates reflex bowel activity
 Best for long term use
33
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Emollient laxatives
◦ Stool softener (Docusate salts)
 Lowers surface tension
 Allows more fat & water to be
absorbed
 When should these be used?
34
◦ Lubricant laxative (mineral oil)
 Lubricates fecal material & intestinal wall
 Prevents H20 from leaking out of gut
 Stool expands & softens
35
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The emollients and lubricants do not seem to
increase peristalsis
◦ Oils a problem in constantly recumbent clients
36
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Hyperosmotic increase water content in large
intestine
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Distends bowel
Increases peristalsis
Evacuates the bowel
Non-absorbable ion exchange
Used before diagnostic tests
37
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Saline laxatives increase osmotic pressure
in small intestine
◦ Inhibit absorption of water & elytes
◦ Increase amount of water & elytes
38
 Results: watery stool
 Increased distention of bowel
 Promotes peristalsis & evacuation
 Example: citrate of magnesia
39
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Stimulant laxatives stimulate nerves
◦ Increases peristalsis
◦ Increase fluid in colon
 Increases bulk
 Softens stool
40
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Few systemic effects
◦ Primary site of action the gut
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Therapeutic Uses
◦ Common constipation
◦ Bowel preparation pre-op, diagnostic tests
41
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Bulk forming: impaction above strictures,
fluid overload, electrolyte imbalance, gas
Emollient: skin rash, decreased absorption
vitamins, lipid pneumonia, elyte imbalance
Hyperosmotic: abdominal bloating, rectal
irritation, elyte imbalance
42
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Saline: magnesium toxicity, elyte imbalance,
diarrhea, increased thirst
Stimulant: nutrient malabsorption, gastric
irritation, elyte imbalance, discolored urine,
rectal irritation
43
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Bulk-forming: interfere with absorption
antibiotics, digoxin, salicylates, oral
anticoagulants
Mineral oil: decrease absorption fat soluble
vitamins
Hyperosmotic: increased CNS depression with
barbiturates, general anesthetics, opioids,
antipsychotics
44
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Oral antibiotics decrease effect of lactulose
Stimulants: decrease absorption antibiotics,
digoxin, tetracycline, oral anticoagulants
45
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Objective 15: identify features of an ideal
laxative and cathartic
◦ What do you think makes an ideal laxative?
46
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Objective 18: describe the major nursing
implications associated with the
administration of laxatives
47
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Assess: drugs client takes including OTC and
herbs
Assess bowel elimination pattern
Assess diet and fluid intake
Assess activity and exercise
Assess for travel, dehydration
Assess for any past GI problems
48
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Objective 19: identify causes of diarrhea
◦ What things, conditions can cause diarrhea?
49
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Objective 20: describe the uses of
antidiarrheal agents
Objective 21: identify the antidiarrheal agents
50
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Antidiarrheal drugs: local or systemic action
◦ Local: adsorb water to cause a formed stool
◦ Systemic: act on autonomic nervous system to
decrease peristalsis
51
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Groups based on mechanism of action
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Adsorbents
Antimotility
Bacterial replacement
Antisecretory
Enzymes
52
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Treat underlying cause
Adsorbents: coat walls of GI tract; bind
causative bacteria, toxin
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Bismuth subsalicylate (Pepto-Bismol)
Attapulgite (Kaopectate)
Aluminum hydroxide (AlternaGel, Maalox)
Kaolin-pectin
53
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Decrease: peristalsis, muscle tone
Use with adsorbents, opiates
Examples:
◦ Atropine
◦ Hyoscyamine
◦ Hyosine
54
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Decrease bowel motility
Reduce pain
Increased absorption of water & elytes
(absorption time)
55
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Adsorbents: bismuth subsalicylate: form of
ASA
Activated charcoal
Side Effects
◦ Adsorbents: can increase bleeding time, dark
stools, tinnitus, metallic taste, blue gums
◦ Anticholinergics: urinary retention, impotence,
anxiety, brady or tachy-cardia, blurred vision,
photophobia
56
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Adsorbents: decrease digoxin, clindamycin,
oral hypoglycemics. Methotrexate-toxicity
Anticholinergics: decreased effect with
antacids. Increased anticholinergic effect with
tricyclic antidepressants, MAOIs, amantadine
& antihistamines
57
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Opiates: additive CNS depression-alcohol,
narcotics, sedative-hypnotics, antipsychotics,
skeletal muscle relaxants
Pepto + oral anticoagulants
58
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Objective 22: describe the nursing
implications associated with antidiarrheal
agents
59
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Assess for cause of diarrhea
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Medications
Infections
Diet
Lactulose intolerance
Emotional stress
Hyperthyroidism
Inflammation of gut
Surgical bypass of gut
60
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Objective 23: discuss the pathophysiology of
nausea and vomiting
◦ Nausea: sensation of abdominal discomfort that is
intermittently accompanied by the desire to vomit
◦ Vomiting: the forceful expulsion of gastric contents
up the esophagus and out of the mouth
61
62
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Objective 24: identify antiemetic drugs and
their classification
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Dopamine antagonists
Serotonin antagonists
Anticholinergics
Corticosteroids
Benzodiazepines
Cannaboinoids
63
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Objective 25: identify the mechanism of
action, indications for use and desired effects
of antiemetic drugs
64
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Phenothiazines, butyrophenones (Haldol) and
metoclopramide (Reglan)
◦ Phenothiazines include Thorazine and Compazine
 Drugs act to inhibit dopamine receptors
that are part of the pathway to the
vomiting center.
 Also block other dopamine receptors in
the brain
 Can cause EPS
65
◦ Phenothiazines mostly used
◦ Reglan popular
66
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Serotonin Antagonists: chemotherapy,
radiation, post op
Block serotonin receptors in the CTZ and GI
tract
Drugs include
◦ Dolasetron (Anzemet); granisetron (Kytril) and
ondansetron (Zofran)
67
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Anticholinergics: counterbalance the amount
of acetylcholine at the CTZ
Often for motion sickness; may see for clients
on chemotherapy
Drug examples
◦ Cyclizene (Marezine), dimenhydrate (Dramamine),
meclizene (Antivert), scopolamine
68
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Corticosteroids
◦ Sometimes see Decadron
◦ Don’t know its action
69
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Cannaboinoids
◦ Active ingredient THC from marijuana
◦ Inhibit various pathways to the CTZ
◦ Drugs include: dronabenol (Marinol)
 Do cause mind altering effects
 Can be abused
70
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Benzodiazepines: various activities such as
sedation, depression of vomiting center, can
cause amnesia
◦ Examples: diazepam, lorazepam and midazolam
71
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New for chemo clients
◦ Neurokinin receptor antagonist
 Aprepitant (Emend)
72
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Objective 26: explain the use of emetics
73
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Emetics are used when the stomach needs to
be emptied
◦ Use after overdose
◦ Example: syrup of Ipecac: NO LONGER used for
kids
 Fresh supplies are needed as the drug
will expire
74
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Objective 27: Describe the nursing process
related to the administration of
emetics/antiemetics
◦ What assessments would you make?
◦ What interventions would you initiate?
75
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Objective 28: demonstrate the ability to
calculate drug dosages
76
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