14- GI II

Question 1

how does 5ht stimulate gastric motility?

Answer 1

induces release of Ach onto smooth muscle (muscarinic receptors)

Question 2

how does dopamine effect gastric motility?

Answer 2

activates presynaptic reeptors to decrease firing of ENS neurons —> decrease gastric motility

Question 3

prokinetic mechanism of metoclopramide

Answer 3

D2 antagonist

Question 4

adverse effects metoclopramide

Answer 4

CNS drowsiness, anxiety

parkinsonian symptoms

Question 5

MOA bethanechol

Answer 5

M3 agonist

Question 6

MOA neostigmine

Answer 6

AchE inhibtor

Question 7

MOA erythromycin

Answer 7

motilin receptor agonist

Question 8

what type of laxative is methylcellulose?

Answer 8

bulk forming

Question 9

what type of laxative is glycerin

Answer 9

surfactant

Question 10

what type of laxative is lactulose

Answer 10

osmotic

Question 11

what type of laxative is senna

Answer 11

stimulant

Question 12

what happens when you stimulate 5HT4 receptors

Answer 12

• promote NT release in ENS resulting in motility

- decrease firing of extrinisc sensory neurons to CNS (blcok pain)

Question 13

how does activation of chloride channels a laxative mechanism

Answer 13

increase luminal concentration of chlroide –> sodium and water go to lumen too

–> stool soft and motility easier

Question 14

when should you use mu-opiod receptor antagonist?

Answer 14

when using opiod agonist to treat pain post surgically

mu-opiod antagonist doesn’t go to CNS = pain relieved and no constipation

Question 15

what type of laxative tegaserod?

Answer 15

5HT partial agonist

Question 16

what type of laxative lubiprostone?

Answer 16

chloride channel activator

Question 17

what are the two mu-opiod receptor antagonists used as laxatives?

Answer 17

methylnaltrexone and alvimopan

Question 18

treat opiod-induced constipation during palliative care

Answer 18

methylnaltrexone

Question 19

treat postop patients with bowel resevtion

Answer 19

alvimopan **only 7 days of high chance MI

Question 20

why can an opiod antagonist be used to treat diarrhea?

Answer 20

opiod decrease peristaltic contraction and increase sphincters and segmental contractions, decrease GI distension perception

Question 21

what effects of bismuth subsalicylate are antidiarrheal?

Answer 21

inhibiton of prostaglandin synthesis in intestines and absorption of bacteria

*stimulates in stomach

Question 22

how is octeotide an antidiarrheal?

Answer 22

acts as a somatostatin agonist

Question 23

MOA ondansetron

Answer 23

5HT3 antagonist

direct antiemetic

— constipation

Question 24

MOA scopolamine

Answer 24

M1 antagonist

direct antiemetic

*** motion sickness

Question 25

what two anitemetics are good for motion sickness?

Answer 25

scopolamine and dimenhydrinate

Question 26

MOA metoclopramide

Answer 26

D2 antagonist direct antiemetic --- parkisonian symptoms

Question 27

MOA dimenhydrinate

Answer 27

H1 antagonist *** motion sickness --- drowsiness

Question 28

MOA aprepitant

Answer 28

NK1 antagonist --- drug-drug interaction

Question 29

MOA prochlorperazine

Answer 29

M1D2H1 antagonist ***only severe nausea and drowsiness , lots of adverse effects

Question 30

MOA lorazepam

Answer 30

GABA agonist indirect antiemetic ***anxiety

Question 31

MOA nabilone

Answer 31

cannabinoid agonist indirect antiemetic **chemo --- dysphoria (high)

Question 32

MOA dexamethasone

Answer 32

clucorticoid agoinst indirect antiemetic --> increases 5HT antagonist --- steroid side effects