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45 Cards in this Set
- Front
- Back
What are the stimuli for acid secretion by parietal cells?
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histamine
gastrin acetylcholine |
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How does acid enter the gastric lumen?
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via the H+/K+ ATPase
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Where are H1 receptors? Where are H2 receptors?
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H1- CNS, respiratory systems
H2- GI system |
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What are the classes of antiemetic drugs?
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antihistamines
phenothiazines anticholinergics antiserotonins NK-1 receptor blockers |
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MOA of antihistamines as antiemetics
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block stimulation of CRTZ and vestibular apparatus
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What antihistamines act as antiemetics?
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diphenhydramine (H1 blocker)
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MOA of phenothiazines as antiemetics
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block action of dopamine on CRTZ and emetic center
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What phenothiazines act as antiemetics?
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Acepromazine
Metaclopramide |
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MOA of serotonin antagonist drugs as antiemetics
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block 5-HT3 receptor to reduce stimulation of CRTZ and vagal afferent neurons
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Which serotonin antagonists act as antiemetics?
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Ondansetron
Metaclopramide at high doses (more side effects) |
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How do anticholinergics prevent vomiting?
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block muscarinic receptors by decreasing vestibular and CRTZ stimulation
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MOA of NK-1 antagonists
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NK-1 is also known as substance P which can trigger vomiting by several mechanisms, blocking it can affect several causes of vomiting
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What are the NK-1 antagonists?
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Maropitant (Cerenia)
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What are prokinetic drugs, and when do you NOT want to use them?
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increase GI motility
Don't use in blocked animals! |
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What are the prokinetic drugs?
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Bethanechol
Metaclopramide Domperidone Cisapride Lidocaine |
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MOA of bethanechol as a prokinetic
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cholinergic muscarinic agonist
muscarinic agonists stimulate GI motility |
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MOA of Metaclopramide as a prokinetic
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uncertain, acts on proximal GI tract
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MOA of Domperidone
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dopamine receptor antagonist in early GIT
*dopamine inhibits GI motility |
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MOA of Cisapride
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5-HT4 agonist, weak 5-HT3 antagonist
acts on entire GI tract |
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MOA of Lidocaine as a prokinetic
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Na+ channel blocker, how that causes increased GI motility is not completely clear
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What are the acid-suppressant drugs?
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misoprostol
magnesium hydroxide cimetidine famotidine sucralfate omeprazole |
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MOA of misoprostol
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PGE analog
-replaces the PGE inhibited by NSAID use, protects from acid damage - used to prevent ulcers, not treat |
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MOA of magnesium hydroxide
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buffer, increases stomach pH
-does not stop/decrease production of acid, just neutralizes it |
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MOA of cimetidine and famotidine
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H2 receptor antagonists
- block stimulation of parietal cell by histamine, so acid secretion is decreased |
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MOA of sucralfate
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coats stomach
-protects and heals ulcers *requires an acidic environment to work, do not use in conjunction with buffers etc |
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MOA of omeprazole
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proton pump inhibitor
-most powerful acid inhibitor -blocks transport of H+ into the gastric lumen |
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List the anti-diarrhea drugs
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Loperamide
Diphenoxylate Atropine Glycopyrrolate |
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MOA of loperamide
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opioid mu agonist
-act locally on mu receptors in GIT, decreasing propulsive contractions and increase GI sphincter tone -also have antisecretory effect |
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MOA of diphenoxylate
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opioid mu agonist
-act locally on mu receptors in GIT, decreasing propulsive contractions and increase GI sphincter tone -also have antisecretory effect *can cross to CNS, cause "high" |
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MOA of atropine and glycopyrrolate
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cholinergic muscarinic antagonist
-decreases GI motility and secretions by blocking parasympathetic input to GIT -not as specific, more side effects |
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List the types of laxatives
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bulk
lubricant saline stimulant stool softeners |
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How do bulk laxatives work? Give an example.
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natural products and plant fibers that resist digestion and attract water to the GIT, increasing mass and stimulating motility
eg: wheat bran |
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How do lubricant laxatives work? Give an example.
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coat the surface of the stool and increase water content
ease passage of stool eg: mineral oil |
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How do saline laxatives work? Give an example.
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draw water into the GIT lumen
eg: magnesium sulfate |
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How do stimulant laxatives work? Give an example.
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mechanism not exactly known, thought to release "active agents" possibly electrolytes that draw water into the GIT
eg: bisacodyl |
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How do stool softeners work? Give an example.
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decrease surface tension and allow water to accumulate in stool
eg: Docusate |
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What are the appetite stimulant drugs?
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benzodiazepines
cyproheptadine mirtazapine |
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MOA of benzodiazepines as appetite stimulants
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increase effects of GABA which triggers appetite
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MOA of cyproheptadine
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serotonin antagonist, histamine antagonist
*serotonin decreases appetite |
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MOA of mirtazapine
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antidepressant (non-specific MOA)
stimulates appetite, especially in cats |
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List the emetics
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apomorphine
xylazine hydrogen peroxide salt |
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MOA of apomorphine
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mu agonist, can trigger vomiting
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MOA of xylazine
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alpha-2 agonist
(not sure how this causes vomiting) *especially works in cats |
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MOA of H2O2
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stimulates pharynx (bubbles)
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MOA of salt
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irritates pharynx, triggers vomiting reflex
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