Transcript Gastrointestinal Drugs

Pharmacology : NURS 1950
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Objective 1: list the components of gastric
juice that contribute to the pain associated
with peptic ulcers
◦ HCL, Pepsin, gastrin, lipase and histamine
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Chief cells
◦ Secrete pepsinogen
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Parietal cells
◦ Stimulated by acetylcholine to produce HCL and
gastrin
◦ Intrinsic factor
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Mucous cells
◦ Coats stomach wall
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Objective 3: list drugs considered to be
ulcerogenic
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Smoking
NSAIDS
Corticosteroids
ASA
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Objective 4: explain the actions of the
antiulcer drugs
◦ Decrease acidity
◦ Block histamine receptors
◦ Gastrointestinal prostaglandins
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◦ Gastric acid pump inhibitors
◦ Coating agents
◦ Prokinetic agents
◦ Antispasmodic agents
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Raise the pH of gastric contents
◦ Higher pH, less acidity
 Decreased pain
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Cheap
Effective
No constipation or diarrhea
No systemic effects
No rebound acidity
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Objective 7: differentiate between the various
antacids
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Riopan, Maalox, Mylanta II,
◦ low sodium
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Calcium carbonate, Aluminum hydroxide:
constipation
Magnesium:
◦ diarrhea, electrolyte imbalance
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Calcium carbonate & sodium bicarbonate:
rebound acidity
Simethicone:
◦ defoaming agent
Alginic acid: highly viscous solution—
sodium alginate
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What are the assessments and interventions
the nurse would do for a client taking an
antacid?
◦ Renal
◦ GI
◦ Schedule of meds
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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?
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◦ Which clients should not use anticholinergics?
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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
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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
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Drugs include
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Cimetidine (Tagamet)
Famotidine (Pepcid)
Nizatidine (Axid)
Rantidine (Zantac)
 Prototype
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Drugs can cause
◦ Dizziness, HA, diarrhea, constipation
◦ If confusion, disorientation, hallucination, see MD
◦ Can cause gynecomastia, hepatotoxicity
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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
◦ S/E: diarrhea, HA, muscle pain and fatigue
◦ If rash: call MD
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Drugs include
◦ Esomeprazole (Nexium)
◦ Lansoprazole (Prevacid)
◦ Omeprazole (Prilosec)
 prototype
◦ Pantoprazole (Protonix)
◦ Rabeprazole (Aciphex)
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Consult with MD
Avoid ETOH
Correct timing
No smoking
Immediately report blood
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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
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Causes of constipation
◦ What are some things or conditions that can cause
constipation?
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Act three ways
◦ Affect fecal consistency
◦ Increase fecal movement
◦ Remove stool from rectum
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Laxatives OTC; misused
◦ Dependence
◦ Damage bowel
◦ Cause problems in bowel
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Caution: surgical abdomen; appendicitis;
N/V; fecal impaction; intestinal obstruction;
undiagnosed abdominal pain
Contraindicated: hypersensitivity
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Bulk-forming
Emollient
Hyperosmotic
Saline
Stimulant
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Bulk-forming: natural fiber-like
◦ Absorb water
◦ Distends bowel
◦ Initiates reflex bowel activity
 Best for long term use
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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?
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◦ Lubricant laxative (mineral oil)
 Lubricates fecal material & intestinal wall
 Prevents H20 from leaking out of gut
 Stool expands & softens
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The emollients and lubricants do not seem to
increase peristalsis
◦ Oils a problem in constantly recumbent clients
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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
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Saline laxatives increase osmotic pressure
in small intestine
◦ Inhibit absorption of water & elytes
◦ Increase amount of water & elytes
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 Results: watery stool
 Increased distention of bowel
 Promotes peristalsis & evacuation
 Example: citrate of magnesia
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Stimulant laxatives stimulate nerves
◦ Increases peristalsis
◦ Increase fluid in colon
 Increases bulk
 Softens stool
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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
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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
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Saline: magnesium toxicity, elyte imbalance,
diarrhea, increased thirst
Stimulant: nutrient malabsorption, gastric
irritation, elyte imbalance, discolored urine,
rectal irritation
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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
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Oral antibiotics decrease effect of lactulose
Stimulants: decrease absorption antibiotics,
digoxin, tetracycline, oral anticoagulants
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Objective 15: identify features of an ideal
laxative and cathartic
◦ What do you think makes an ideal laxative?
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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
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Objective 19: identify causes of diarrhea
◦ What things, conditions can cause diarrhea?
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Objective 20: describe the uses of
antidiarrheal agents
Objective 21: identify the antidiarrheal agents
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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
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Groups based on mechanism of action
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Adsorbents
Antimotility
Bacterial replacement
Antisecretory
Enzymes
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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
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Decrease: peristalsis, muscle tone
Use with adsorbents, opiates
Examples:
◦ Atropine
◦ Hyoscyamine
◦ Hyosine
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Decrease bowel motility
Reduce pain
Increased absorption of water & elytes
(absorption time)
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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
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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
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Opiates: additive CNS depression-alcohol,
narcotics, sedative-hypnotics, antipsychotics,
skeletal muscle relaxants
Pepto + oral anticoagulants
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Objective 22: describe the nursing
implications associated with antidiarrheal
agents
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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
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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
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Dopamine antagonists
Serotonin antagonists
Anticholinergics
Corticosteroids
Benzodiazepines
Cannaboinoids
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Objective 25: identify the mechanism of
action, indications for use and desired effects
of antiemetic drugs
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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
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◦ Phenothiazines mostly used
◦ Reglan popular
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chemotherapy, radiation, post op
Block serotonin receptors in the CTZ and GI
tract
Drugs include
◦ Dolasetron (Anzemet); granisetron (Kytril) and
ondansetron (Zofran)
 prototype
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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
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◦ Sometimes see Decadron
◦ Don’t know its action
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◦ Active ingredient THC from marijuana
◦ Inhibit various pathways to the CTZ
◦ Drugs include: dronabenol (Marinol)
 Do cause mind altering effects
 Can be abused
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various activities such as sedation,
depression of vomiting center, can cause
amnesia
◦ Examples: diazepam, lorazepam and midazolam
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New for chemo clients
◦ Neurokinin receptor antagonist
 Aprepitant (Emend)
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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
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◦ What assessments would you make?
◦ What interventions would you initiate?
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