Pharm: Antiemetic Agents

Question 1

What brainstem structure coordinates vomiting?

Answer 1

Nucleus tractus solitarius (think the solitary track runner)

Question 2

Where is the NTS located?

Answer 2

Medulla

Question 3

The NTS receives inputs from ______________, _______________, and _________________.

Answer 3

• GI tract
• vestibular system
• area postrema

Question 4

What CN connects the Gi tract directly to the NTS?

Answer 4

X - vagus (think of the neon Vegas sign on the stomach-shaped dirt area)

Question 5

By what NT and mechanism does GI irritation cause vomiting?

Answer 5

5-HT released from stomach gastric cells (think the smiley hammer) act on 5HT-3 receptors on vagal afferents (think of 1-2-3 Hammer Throw! sign next to the hammer athlete)

Question 6

What system is responsible for motion sickness and vertigo?

Answer 6

Vestibular system (think of the rower in the (semicircular) canal with the vest)

Question 7

Where is the chemoreceptor trigger zone?

Answer 7

area postrema (think of the extreme postures next to the track)

Question 8

Where is the area postrema located?

Answer 8

The area postema (aka chemoreceptor-trigger zone) is adjacent to the NTS in the 4th ventricle (not protected by BBB)
- can respond to both CFS and blood

Question 9

Odansetron blocks ________________.

Answer 9

5HT3 receptors on the vagal nerve4 (think of the dancer standing in the way of the hammer throw)

Question 10

Although odansetron is generally well tolerated, what are the most common side effects?

Answer 10

1. constipation (runner with the serotonin cord wrapped around his waist)
2. headache (runner getting hit in the head with a smiley hammer)
3. 5HT syndrome with concomitant SSRI use (think of the pile of smiley hammers)
4. prolonged QT (think of the dancer’s ribbon with the squiggle for torsades)

Question 11

What part of the vomiting response do 1st gen antihistamines block?

Answer 11

H1 receptors- Gq receptors in the vestibular system (think of the bees going to the H1- Q dandelions by the canal)

Question 12

Which muscarinic receptor isotope do anti-emetics work on?

Answer 12

M1 (think motorcycle parking for the 1st place rowers)

Question 13

What anti-muscarinic drug is used to treat sea sickness?

Answer 13

scopolomine (think of the rower in the sailor outfit with a scope)

Question 14

Area postrema has what two receptors?

Answer 14

1. D2 (extreme posture gymnast on the D rings)

2. NK1 (gymnast on the plaNK1)

Question 15

What drug blocks D2 receptors of the area postrema?

Answer 15

Metaclopramide (think of the cheater TiCkLing the gymnast)

Question 16

What is a potentially useful side effect of metoclopromide?

Answer 16

tx of non-obstructive ileus as a prokinetic drug (think of the landing area and the gymnast falling the stomach pad)

Question 17

What are side effects of metoclopromide?

Answer 17

1. diarrhea (prokinetic)
2. drowsiness (sleeping judge)
3. extrapyramidal signs (judge with pyramid hat)
4. Malignant neuroleptic syndrome (judge eating Now More Spicy Chicken)
5. Hyperprolactinemia (judge spewing milk)
6. Depression (depressed coach)

Question 18

What ligand binds to the NK1 receptors?

Answer 18

Substance P (think of the line checking for pee SUBSTANCES near the guy plaNKing)

Question 19

The drug _________________ blocks NK1 receptors.

Answer 19

Aprepitant (“all PaRticiPANTs must undergo urine screening”)