Gastrointestinal Drugs

Front 1

What are the stimuli for acid secretion by parietal cells?

Back 1

histamine
gastrin
acetylcholine

Front 2

How does acid enter the gastric lumen?

Back 2

via the H+/K+ ATPase

Front 3

Where are H1 receptors? Where are H2 receptors?

Back 3

H1- CNS, respiratory systems
H2- GI system

Front 4

What are the classes of antiemetic drugs?

Back 4

antihistamines
phenothiazines
anticholinergics
antiserotonins
NK-1 receptor blockers

Front 5

MOA of antihistamines as antiemetics

Back 5

block stimulation of CRTZ and vestibular apparatus

Front 6

What antihistamines act as antiemetics?

Back 6

diphenhydramine (H1 blocker)

Front 7

MOA of phenothiazines as antiemetics

Back 7

block action of dopamine on CRTZ and emetic center

Front 8

What phenothiazines act as antiemetics?

Back 8

Acepromazine
Metaclopramide

Front 9

MOA of serotonin antagonist drugs as antiemetics

Back 9

block 5-HT3 receptor to reduce stimulation of CRTZ and vagal afferent neurons

Front 10

Which serotonin antagonists act as antiemetics?

Back 10

Ondansetron
Metaclopramide at high doses (more side effects)

Front 11

How do anticholinergics prevent vomiting?

Back 11

block muscarinic receptors by decreasing vestibular and CRTZ stimulation

Front 12

MOA of NK-1 antagonists

Back 12

NK-1 is also known as substance P which can trigger vomiting by several mechanisms, blocking it can affect several causes of vomiting

Front 13

What are the NK-1 antagonists?

Back 13

Maropitant (Cerenia)

Front 14

What are prokinetic drugs, and when do you NOT want to use them?

Back 14

increase GI motility
Don't use in blocked animals!

Front 15

What are the prokinetic drugs?

Back 15

Bethanechol
Metaclopramide
Domperidone
Cisapride
Lidocaine

Front 16

MOA of bethanechol as a prokinetic

Back 16

cholinergic muscarinic agonist

muscarinic agonists stimulate GI motility

Front 17

MOA of Metaclopramide as a prokinetic

Back 17

uncertain, acts on proximal GI tract

Front 18

MOA of Domperidone

Back 18

dopamine receptor antagonist in early GIT
*dopamine inhibits GI motility

Front 19

MOA of Cisapride

Back 19

5-HT4 agonist, weak 5-HT3 antagonist
acts on entire GI tract

Front 20

MOA of Lidocaine as a prokinetic

Back 20

Na+ channel blocker, how that causes increased GI motility is not completely clear

Front 21

What are the acid-suppressant drugs?

Back 21

misoprostol
magnesium hydroxide
cimetidine
famotidine
sucralfate
omeprazole

Front 22

MOA of misoprostol

Back 22

PGE analog
-replaces the PGE inhibited by NSAID use, protects from acid damage
- used to prevent ulcers, not treat

Front 23

MOA of magnesium hydroxide

Back 23

buffer, increases stomach pH
-does not stop/decrease production of acid, just neutralizes it

Front 24

MOA of cimetidine and famotidine

Back 24

H2 receptor antagonists
- block stimulation of parietal cell by histamine, so acid secretion is decreased

Front 25

MOA of sucralfate

Back 25

coats stomach
-protects and heals ulcers
*requires an acidic environment to work, do not use in conjunction with buffers etc

Front 26

MOA of omeprazole

Back 26

proton pump inhibitor
-most powerful acid inhibitor
-blocks transport of H+ into the gastric lumen

Front 27

List the anti-diarrhea drugs

Back 27

Loperamide
Diphenoxylate
Atropine
Glycopyrrolate

Front 28

MOA of loperamide

Back 28

opioid mu agonist
-act locally on mu receptors in GIT, decreasing propulsive contractions and increase GI sphincter tone
-also have antisecretory effect

Front 29

MOA of diphenoxylate

Back 29

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"

Front 30

MOA of atropine and glycopyrrolate

Back 30

cholinergic muscarinic antagonist
-decreases GI motility and secretions by blocking parasympathetic input to GIT
-not as specific, more side effects

Front 31

List the types of laxatives

Back 31

bulk
lubricant
saline
stimulant
stool softeners

Front 32

How do bulk laxatives work? Give an example.

Back 32

natural products and plant fibers that resist digestion and attract water to the GIT, increasing mass and stimulating motility
eg: wheat bran

Front 33

How do lubricant laxatives work? Give an example.

Back 33

coat the surface of the stool and increase water content
ease passage of stool
eg: mineral oil

Front 34

How do saline laxatives work? Give an example.

Back 34

draw water into the GIT lumen
eg: magnesium sulfate

Front 35

How do stimulant laxatives work? Give an example.

Back 35

mechanism not exactly known, thought to release "active agents" possibly electrolytes that draw water into the GIT
eg: bisacodyl

Front 36

How do stool softeners work? Give an example.

Back 36

decrease surface tension and allow water to accumulate in stool
eg: Docusate

Front 37

What are the appetite stimulant drugs?

Back 37

benzodiazepines
cyproheptadine
mirtazapine

Front 38

MOA of benzodiazepines as appetite stimulants

Back 38

increase effects of GABA which triggers appetite

Front 39

MOA of cyproheptadine

Back 39

serotonin antagonist, histamine antagonist
*serotonin decreases appetite

Front 40

MOA of mirtazapine

Back 40

antidepressant (non-specific MOA)
stimulates appetite, especially in cats

Front 41

List the emetics

Back 41

apomorphine
xylazine
hydrogen peroxide
salt

Front 42

MOA of apomorphine

Back 42

mu agonist, can trigger vomiting

Front 43

MOA of xylazine

Back 43

alpha-2 agonist
(not sure how this causes vomiting)
*especially works in cats

Front 44

MOA of H2O2

Back 44

stimulates pharynx (bubbles)

Front 45

MOA of salt

Back 45

irritates pharynx, triggers vomiting reflex