wk 3 13 - physiology and pharmacology of nausea and vomiting

Question 1

associated feeling of nause

Answer 1

a sinking sensation
im going to be sick
felt in throat and stomach

Question 2

t/f nausea often relieved by vomiting

Answer 2

true

Question 3

associated signs symptoms of nausea

Answer 3

pallor
excessive secretions - salivation 
relaxation of stomach/ lower oesophagus
upper intestinal contractions (jejunum,duodenum) 
reverse peristalsis

Question 4

t/f vomiting can occur without nausea

Answer 4

true

Question 5

retching

Answer 5

repetitive reverse peristalsis without vomiting

Question 6

forceful conraction involuntary of whatt skeletal muscles is seen in retching

Answer 6

abdominal muscles
diaphragm
(cardiac part of stomach pushed into thorax)

Question 7

medical term for vomiting

Answer 7

emesis

Question 8

outline immediate change seen prior vomiting in mouth

Answer 8

breathing stopped(elevation of soft palate, closing of epiglotttis)

Question 9

outline vomiting

Answer 9

suspension of intestinal slow wave activity

retrogade contractions of ileum to stomach

breathing stopped (softpalate…)

relaxation of stomach -dia+abdomino contraction

ejection of gastrc contents

cycle repeated

Question 10

t/f voomiting involved contraction of stomach

Answer 10

false

relaxed so can recieve contents from sml intestine

Question 11

which cells are stimulated inducing vomiting

Answer 11

enterochromffin cells
release mediators -
5-HT, substance P

Question 12

what happens when 5-ht released

Answer 12

diffises locally
stimulates vagus nerves (via 5-HT3 receptors)
causes depolarisation, from gut to brain stem (chemoreceptor trigger zone, nucleus tractus soitarious) -NEED TO KNOW

Question 13

other than toxic materials entering gut, what else can stimulate enterchromaffin cells

Answer 13

systemic toxins (cytotoxic drugs)

Question 14

oter than mechanical stimuli or absorbed toxins, what else can induce vomiting

Answer 14

vestibular system (motion sickness)

stimuli within CNS (pain, fear, anticipation)

Question 15

which 2 areas does the signalling pass thhrough for vomiting induced due to stimuli within th CNS

Answer 15

limbic system
cerebral cortex

then travels to medulla

Question 16

motion sickness signals through

Answer 16

vestibular nucleus then to medulla

Question 17

vomiting centre

Answer 17

diffuse collection of neurones

used to coordinate appropriate response

Question 18

vagal efferent effect on stomach/oesophagus/sml intestine in vomiting

Answer 18

oeso - shorterning
stomach - proximal relaxation
sml intestine - giant retrogade contraction

Question 19

effect of somatic motor neurones

Answer 19

controls skeletal muscles involved in vomiting

Question 20

autonomic/somatic ouputs effect on vomiting (immediately precede)

Answer 20

incr hr
incr secretion
skin - pallor, cold sweat (vasoconstriction of vessels)
constricyion of bladder and anus sphincters

Question 21

vomiting (prolonged/severe) causes

Answer 21

dehydration
loss gastric contents - less protons, chloride (acid) - hypochloraemic metabolic alkalosis - incr pH of blood
hypokalaemia - proton loss = potassium loss mediated by kidney

duodenal bicarbonate may cause metabolic acidosis (v severe)

oesophageal damage (mallory-weiss tear)

Question 22

drugs and radiation induced emesis

Answer 22

cancer chemo - cisplatin, doxorubicin

radiotherapy - 5-HT,subP release

general anaesthetic (Post Operative Nausea and Vomiting PONV)

dopamine agonists (levodopa - parkinsons) (high conc of D2 receptors in CTZ)

morphine/opiates

cardiac glycosides (digoxin)

drugs enhancing 5-HT function

Question 23

pattern with 5-Ht3 receptor antagonist drug names

Answer 23

all end in setron

ondansetron, palonosetron

Question 24

which type of emesis is 5-ht3 antagonists effective against

Answer 24

chemo/radiation induced

post-op nausea

Question 25

5-ht3 antagonists block peripheral and central receptors, what does this preven

Answer 25

signals travelling to AP and NTS

Question 26

t/f 5-ht3 antagonists are less effective in repeated rounds of chemo

Answer 26

true

Question 27

what may be added to 5-ht3

Answer 27

corticosteroids or neurokinin receptor antagonist (NK) (inhibits subP)

Question 28

5-ht3 is not effective in preventing vomiting due to motion sickness, what drugs are

Answer 28

histamine H1 receptor antagonists

Muscarinic ACh receptor antagonists

Question 29

2 muscarinic ach drugs

Answer 29

hyosine

scopolamine

Question 30

administration of muscarinic ach’s

Answer 30

transdermal patch

Question 31

where are muscarinic receptors that are blocked through mus.AC|h antagonists

Answer 31

vestibular nuclei
NTS
vomiting centre

Question 32

blurred vision 
urinary retention 
dry outh 
sedation
why does this occur with muscarinic Ach antagonists?

Answer 32

blockage of parasympathetic divsion of ANS

Question 33

other than prophylaxis and motion sickness, when would histamine H1 receptor antagonists be used

Answer 33

acute labrynthitis

irritant induced nausea

Question 34

t/f Histamine H1 receptors block H1 in VS and NTS

Answer 34

false

VS
NTS
Muscarinic receptor

Question 35

adverse effects of H1

Answer 35

cns depression

sedation

Question 36

domperidome and metoclopramide are

Answer 36

dopamine antagonists

Question 37

dopamine antagonists are effective in treating q

Answer 37

drug induced vomiting

vomiting from GI disorders

Question 38

phenothiazine is used in

Answer 38

severe nausea

Question 39

as well as blocking D2,D3 in CTZ, what other effect does domperidome have

Answer 39

prokinetic actioin on oesophagus/stomach/intestine

Question 40

in acute highly emetic chemotherapy, which 3 drugs would be given

Answer 40

NK1 receptor antagonist
5-HT3 receptor antagonist
Dexamethasone

Question 41

t/f for delayed emesis from chemo, same 3 drugs used in acute

Answer 41

false

only 2 - NK1 + Dexamethasone