Cancer Tx-Related Tox - N/V

Question 1

Most common AEs of chemotx?

Answer 1

N/V

Question 2

How should N/V tx be approached?

Answer 2

It should be prevented before it actually happens

Question 3

What’s acute CINV?

Answer 3

occurs ≤ 24h post-chemo

Question 4

What’s delayed CINV?

Answer 4

occurs > 24h post-chemo

Question 5

What’s anticipatory CINV?

Answer 5

Occurs as a conditioned response due to past neg experience BEFORE receiving next tx

Question 6

What’s breakthrough CINV?

Answer 6

Occurs despite N/V prophylaxis

Question 7

NTs involved in CINV?

Answer 7

5-HT3, Substance P

Question 8

How does chemotx-induced release of serotonin bring about CINV?

Answer 8

It causes release of SEROTONIN in the GIT (peripherally) and via vagus nerve stimulation of the vomiting centre (centrally)

Question 9

How is substance P involved in CINV?

Answer 9

It stimulates NK-1 receptors in the CNS

Question 10

What type of CINV is usually assoc w/ substance P and its stimulation of NK-1 receptors?

Answer 10

Delayed CINV

Question 11

How does EtOH intake affect the CTZ?

Answer 11

It makes the CTZ LESS sensitive > less likely to vomit

Question 12

What is a biphasic pattern of emesis?

Answer 12

When there’s one early and large episode of acute vomiting, then a second prolonged, less intense peak of vomiting

Question 13

What’s a monophasic pattern of emesis?

Answer 13

When there’s a long interval of moderately intense emesis ~6h post-tx

Question 14

4 emetic risk gps:

Answer 14

HIGH: risk in > 90% of pts

MOD: risk in 30-90% of pts

LOW: risk in 10-30% of pts

MINIMAL: risk in < 10% of pts

Question 15

Serotonin receptor (5-HT3) antagonist drugs:

Answer 15

ondansetron, granisetron

Question 16

MOA of 5-HT3 antagonists

Answer 16

bind to 5-HT receptors in CTZ and in vagal afferent fibres from the upper GIT

Question 17

How is the efficacy of 5HT3 antagonists usually improved?

Answer 17

by adding a CS (usually dexamethasone)

Question 18

AEs of 5-HT3 receptor antagonist

Answer 18

h/a, constipation

Question 19

What kind of emesis is tx’ed by 5-HT3 receptor antagonists?

Answer 19

acute CINV

Question 20

Risks assoc w/ higher doses of 5-HT3 receptor antagonists?

Answer 20

QT prolongation

Question 21

Preferrend 5-HT3 receptor antagonist?

Answer 21

Palonosetron (longer half life, single dose, less concern w/ QT prolongation)

Question 22

MOA of neurokinin-1 (NK-1) receptor antagonists?

Answer 22

blocks substance P from binding to NK-1 receptors in the CNS

Question 23

When are neurokinin-1 (NK-1) receptor antagonists given?

Answer 23

Day 1 BEFORE chemotx

Question 24

What should be kept in mind when giving neurokinin-1 (NK-1) receptor antagonists with dexamethasone?

Answer 24

Dexa dose should be reduced 50% due to CYP interactions (CYP3A4 and CYP 2C9)

Question 25

T or F: The action of neurokinin-1 (NK-1) receptor antagonists is canceled out when given concurrently with 5-HT3 receptor antagonists like ondansetron

Answer 25

F They work synergistically, actually

Question 26

neurokinin-1 (NK-1) receptor antagonists can be used for which types of CINV?

Answer 26

Acute and delayed

Question 27

Wrt CINV, CS monotx is used for...

Answer 27

low emetogenic chemo

Question 28

Wrt CINV, how are CS's used for highly emetic and moderately emetic chemo?

Answer 28

CS is combined w/ a 5-HT3 receptor antagonist +/- NK1 receptor antagonist or olanzapine

Question 29

What kind of CINV is prophylaxed w/ CSs?

Answer 29

acute and delayed CINV

Question 30

MOA of CS for CINV?

Answer 30

Not sure (perhaps prostaglandin inhibition plays a role)

Question 31

Steroid of choice for CINV?

Answer 31

Dexamethasone

Question 32

How're dopamine antagonists used in CINV?

Answer 32

Mainly for breakthrough CINV

Question 33

Risk of domperidone (dopamine antagonist)?

Answer 33

QT prolongation

Question 34

What's used for preventing anticipatory emesis?

Answer 34

benzos

Question 35

T or F: BZDs are not great as antiemetics

Answer 35

T

Question 36

Olanzapine MOA in CINV?

Answer 36

acts on several receptors: DA, 5-HT3, histamine, ACh, and muscarinic

Question 37

Olanzapine is effective in preventing this.

Answer 37

Delayed N (nausea only)

Question 38

How is olanzapine used in high and mod emetogenic chemotx?

Answer 38

In combo w/ 5-HT3 receptor antagonist and dexamethasone (+/- NK1 receptor antagonist)

Question 39

dimenhydrinate MOA

Answer 39

Histamine antagonist

Question 40

Dimenhydrinate place in tx for CINV?

Answer 40

PRN for acute sx ctrl

Question 41

Cannabinoids/medical marijuana place in tx for CINV?

Answer 41

Refractory N/V only

Question 42

Efficacy of cannabinoids in CINV?

Answer 42

Not v. effective

Question 43

T or F: Immediate antiemetic regimen alteration should take place if breakthrough N/V is occurring

Answer 43

F Must exclude other dz and med-related causes for emesis first

Question 44

When should you refer a CINV pt?

Answer 44

prolonged N/V, sig. wt loss, sx's of dehydration, fever, abdominal pain, blood or "coffee grounds" in vomitus, altered consciousness

Question 45

Non-pharm approaches for CINV

Answer 45

eat small, freq meals, bland foods (no spicy or acidic foods), calorie-dense foods, eat foods at rm temp