Anti-emetics

Question 1

What are the 5 things that stimulate vomiting?

Answer 1

1. Sight/smell/pain/emotion that directly stimulates the limbic system
2. Motion stimulating CN 8
3. Taste stimulating CN 7, 9, 10
4. Vagal/visceral afferents from GI to CTZ (chemoreceptor trigger zone) and VC (vomiting center) directly
5. Blood concentration of emetics/CSF stimulate CTZ

Question 2

All of the stimuli for vomiting stimulate it where?

Answer 2

Vomiting center in the area postrema of the medulla

Question 3

What drug makes you vomit? (not on CDL)

Answer 3

Tincture of ipecac (remember the Family guy?)

Question 4

What are the 5 classes of drugs used to treat emesis?

Answer 4

1. Anticholinergics
2. Antihistamines
3. Anti-dopaminergics
4. Serotonin antagonists
5. Misc. anti-emetics

Question 5

How do the anti-histamines work?

Answer 5

H1 antagonists; older antihistamines that are also anticholinergics. Vestibular & vagal blockers (as opposed to anticholinergics which only block vagal stimulation)

Question 6

Which anti-emesis drug is OTC for motion sickness?

Answer 6

Cyclizine

Question 7

MOA & clinical use of Meclizine?

Answer 7

H1 antagonist; depresses hyperstimulation of labyrinth; used for vestibular disturbance (Vertigo & Menier’s dz)

Question 8

What anti-dopaminergics are on the CDL?

Answer 8

1. Chlorpromazine
2. Droperidol
3. Metoclopramide

Question 9

Chlorpromazine MOA?

Answer 9

Centrally acting anticholinergic & anti-dopaminergic. Used for N/V and intractable hiccough

Question 10

Droperidol MOA?

Answer 10

Blocks D2 in CTZ. Used for post-operative N/V

Question 11

Metoclopramide MOA?

Answer 11

Used to prevent chemo induced N/V and post-op N/V. Stimulates gastric emptying

Question 12

What are the serotonin antagonists on the CDL?

Answer 12

1. Granisetron

2. Dolasetron

Question 13

Serotonin antagonists MOA in general?

Answer 13

block 5-HT3 in stomach and SI. these organs stimulate CTZ/VC thru Vagus & nucleus tractus solitarius. They also block 5-HT3 in the CTZ. MOST EFFECTIVE ANTI-EMETICS! Effective alone but can be used w/ steroids & benzodiazapines

Question 14

What stands out about Granisetron?

Answer 14

Very potent

Question 15

What stands out about Dolasetron?

Answer 15

Longer half life than other 5-HT3 blockers.

Dolasetron lasts and lasts

Question 16

What is the corticosteroid that can be given for anti-emesis?

Answer 16

Methyl prednisolone

Question 17

Why is methyl prednisolone useful?

Answer 17

It increases the anti-emetic effect of other drugs and decreases the side effects of the other drugs (I guess b/c u can lower the dose of the other drug with the addition of the steroid).

Question 18

Methyl prednisolone also has its own anti-emetic effect. Describe it

Answer 18

Decreases PG’s from chemo/radiation

Question 19

MOA of Aprepitant?

Answer 19

Substance P/neurokinin 1 receptor antagonist.

Question 20

Aprepitant is used for?

Answer 20

Given adjunct with chemo to prevent N/V

Question 21

Unique things about Aprepitant? (3)

Answer 21

1. Crosses BBB so acts centrally
2. CYP3A4 metabolized
3. Tmax= 4 hours. Half life = 10hrs

Question 22

What benzodiazepine is on the CDL? MOA?

Answer 22

Lorazepam. Given adjunct with other anti-emetics prior to chemo (causes somnolence & amnesia that lasts hours).
**Lorazepam makes you too Lazy to vomit

Question 23

What is the anticholinergic that treats vomiting? Specifically what type of vomiting does it treat?

Answer 23

Scopolamine- prophylaxis for motion sickness. Its the patch you put behind your ear

Question 24

MOA of Scopolamine?

Answer 24

Vagal blocker; specifically blocks M1 activation and stimulation of CN VIII (which fires cholinergic stimulation to vomiting center in medulla)

Question 25

AEs of Scopolamine?

Answer 25

Sedation, dry mouth, drowsiness

Question 26

What anti-emesis drugs treat motion sickness?

Answer 26

Scopolamine, Cyclizine, Meclizine**

**Meclizine treats vestibular disturbance (Vertigo & Menier’s dz which cause a perceived motion sickness)

Question 27

What is the treatment regimen for the anticipatory N/V that comes with chemo tx?

Answer 27

Give a serotonin antagonist + another drug (like methyl prednisolone, Lorazepam, Aprepitant, or D2 antagonist)