Anti-emetics

Question 1

what are the 3 categories of causes of nausea and vomitting to VC?

Answer 1

visceral stimulation
CTZ
higher cortical imputs

Question 2

what visceral stimulation causes N+V?

Answer 2

afferents from GIT
can be SNS or PSNS -> mainly vagal
triggered by direct visceral irritation or distension

Question 3

what neurotransmitters are involved in visceral stimulation

Answer 3

5HT
dopamine

Question 4

how does the CTZ cause N+V?

Answer 4

outside blood brain barrier so is exposed to systemic toxins and drugs
triggered by drugs hormones toxins or metabolic abnormalities

Question 5

what neurotransmitters are involved in CTZ

Answer 5

5HT and dopamine

Question 6

how does higher cortical inputs contribute to N+V?

Answer 6

cranial nerves CNVIII and IX
triggered by emotion smell motion sickness vertigo gag reflex

Question 7

what neurotransmitters are involved in higher cortical inputs

Answer 7

Ach 5HT and histamine

Question 8

what are the different classes of antiemetics

Answer 8

antihistamines
antimuscarinic
dopamine R antagonist
anti-psycohotics
5ht3 R antagonists
dexamethasone

Question 9

common causes of N+V

Answer 9

Question 10

features of chemical N+V

Answer 10

Persistent, often severe nausea, unrelieved
by vomiting, aggravated by the sight/smell
of food, drowsiness/confusion

Question 11

drug for chemical N+V

Answer 11

haloperidol
metoclopramide

Question 12

gastric stasis symptoms

Answer 12

Fullness/regurgitation, reduced appetite,
vomiting (often large volume) relieves
nausea, epigastric discomfort, hiccups

Question 13

gastric statsis N+V medication

Answer 13

metoclopramide
domperidone

Question 14

bowel obstruction symptoms

Answer 14

High: regurgitation, forceful vomiting of
undigested food
Low: colicky pain, large faeculant vomits,
visible peristalsis

Question 15

bowel obstruction N+V medication

Answer 15

cyclizine
dexamethasone

Question 16

raised ICP symptoms

Answer 16

Nausea worse in the morning
Projectile vomiting. worse on head
movement, headache

Question 17

raised icp N+V medication

Answer 17

cyclizine
dexamethasone

Question 18

anxiety N+V

Answer 18

benzo

Question 19

post op N+V

Answer 19

caused by serotonin release
tx with ondansetron

Question 20

what increases the risk of chemo-induced N+V

Answer 20

specific chemo agents
females
age<50
past hx of n+V

Question 21

what is aprepitant

Answer 21

an NK1 antagonist used in CINV and intractable vomitting in EOL care
augments use of 5HT3 and dex

Question 22

drug regimen for mechanical bowel obstruction with colic

Answer 22

cyclizine
hyoscine butylbromide
ocreotide