Antinauseants

Question 1

Drugs which cause nausea and vomiting

Answer 1

• Chemotherapy drugs
• Cholinergic agonists
• Dopaminergics
• Opioids

Question 2

Key areas mediating N/V in BBB

Answer 2

• Emetic Center

- Nucleus Tractus Solitarius

Question 3

Key areas mediating N/V outside the BBB

Answer 3

Chemoreceptor trigger zone

Serotonin and muscarinic receptors in the gut

Question 4

Anti-nauseant categories

Answer 4

H1 antagonists 
Anti-muscarinic 
Serotonin antagonists 
Corticosteroids
Neurokinin-1 antagonists 
D2 antagonists 
Cannabinoids

Question 5

H1 antagonists example

Answer 5

Dimenhydrinate (Gravel)

Question 6

Dimenhydrinate mechanism

Answer 6

Blocks receptors in the NTS and inner ear, inhibits stimulation of the emetic center

• also has anticholinergic effects (reduces peristalsis in the GI tract)
• For motion sickness, must allow 30 minutes to absorb

Question 7

Dimenhydrinate side effects

Answer 7

• Drowsiness (help patients sleep)

- Anticholinergic effects: dry mouth

Question 8

Routes of administration of Dimenhydrinate

Answer 8

Oral, Rectal, Parenteral

Question 9

Muscarinic Antagonist example

Answer 9

Scopolamine

Question 10

Scopolamine receptors

Answer 10

CNS: inner ear, NTS, CTZ
Gut: reduce peristalsis
- Can be used as a patch

Question 11

Serotonin antagonist example

Answer 11

Ondansetron - key role in chemo-induced nausea and vomiting (CINV)

Question 12

Serotonin receptors in

Answer 12

Gut: peristalsis, signal nausea
CNS: NTS, CTZ

Question 13

Serotonin antagonists side effects

Answer 13

Constipation - related to reduced peristalsis

Question 14

Corticosteroid example

Answer 14

Dexamethasone

Question 15

Dexamethasone used to treatment and mechanism

Answer 15

• reserved for severe N/V
• useful in cases of raised intracranial pressure
• reduces inflammation

Question 16

Corticosteroids side effects

Answer 16

Systemic corticosteroids have significant side effects so should be used short-term

Question 17

Neurokinin antagonist example

Answer 17

Aprepitant

Question 18

NK-1 receptors located in

Answer 18

emetic center and the CTZ

• blocking these inhibits N/V
• most commonly used in CINV

Question 19

NK-1 antagonist side effects

Answer 19

Hiccups
Anorexia
Fatigue

Question 20

Cannabinoids uses

Answer 20

• used for many years to treat nausea and vomiting
• also stimulate appetite
• reduces anxiety

Question 21

Benzodiazepines uses

Answer 21

Address anxiety associated with N/V

Question 22

Safe drugs used in pregnancy for morning sickness

Answer 22

Pyridoxine
Pyridoxine/Doxylamine
Dimenhydrinate

Question 23

Doxylamine

Answer 23

• is and H1 receptor antagonist