Unit 2- Antiemetics

Question 1

Emesis Trigger Centers

Answer 1

Vomiting center, chemoreceptor trigger zone, cerebral cortex, and vestibular apparatus

Question 2

Vomiting Center

Answer 2

Located in medulla oblongata and receives input from CTZ, vestibular disturbance, higher cortical centers, and peripheral sensory

Question 3

CTZ Receptors

Answer 3

5-HT3, D2, opioid R, NK1, CB1

Question 4

Pharynx and GI Receptors

Answer 4

5-HT3, 5-HT4, D2

Question 5

Vestibular Receptors

Answer 5

H1, Ach M3/5

Question 6

Histamine receptor

Answer 6

H1

Question 7

Serotonin Receptor

Answer 7

5-HT3

Question 8

Substance P Receptor

Answer 8

NK1

Question 9

GABA Receptor

Answer 9

GABA A and GABA B

Question 10

Acetylcholine Receptor

Answer 10

M1

Question 11

Dopamine Receptor

Answer 11

D2

Question 12

Endorphin Receptors

Answer 12

opioid receptors and CB1

Question 13

Therapeutic Emetics

Answer 13

Apomorphine, hydrogen peroxide, xylazine, medetomidine, midazolam/hydromorphone

Question 14

Dog CTZ Receptors

Answer 14

Increase D2 receptors make emesis stimulation more successful, increased H1 receptors

Question 15

Cat CTZ Receptors

Answer 15

Decreased D2 receptors, increased sensitivity to α2 receptors

Question 16

Apomorphine

Answer 16

Dopamine agonist, antagonist to serotonin and adrenergic receptors, more successful in dogs, may have opioid like effects

Question 17

Apomorphine Administration

Answer 17

IV reaches CTZ before crossing BBB to reach emesis center that prevents emesis

Question 18

Apomorphine Sedative Reversal

Answer 18

Opioid antagonists like naloxone

Question 19

Apomorphine Emesis Reversal

Answer 19

Dopaminergic antagonist like Acepromazine

Question 20

Cat Emetics

Answer 20

α2-agonists: xylazine and medetomidine/dexmedetomidine that are highly lipophilic and directly reach receptors in the brain and GI

Question 21

Xylazine

Answer 21

α2 antagonist, common in cats, not reliable in dogs, use lower doses than for sedation

Question 22

Serotonin 5-HT3 Antagonists

Answer 22

Ondansetron and granisetron, block 5-HT3 in VC and CTZ for chemotherapy nausea

Question 23

Serotonin 5-HT3 Antagonist Adverse Effects

Answer 23

Headache, dizziness, itching, constipation, ECG abnormalities

Question 24

Prokinetic D2 Antagonists

Answer 24

Metoclopramide, domperidone

Question 25

Neuroleptic D2 Antagonists

Answer 25

Chlorpromazine and Droperidol

Question 26

D2 Antagonists

Answer 26

Block D2 and serotonin receptors in CTZ, used for vomiting of non-specific cause

Question 27

D2 Antagonist Adverse Effects

Answer 27

Dyskinesia, sedation, postural hypotension, extrapyramidal symptoms

Question 28

Substance P Antagonists

Answer 28

Aprepitant, Cerenia, binds neurokinin 1 receptor in VC to treat motion sickness, chemotherapy vomiting, post-op vomiting

Question 29

Substance P Antagonist Adverse Effects

Answer 29

Dyskinesia, sedation, dizziness, hiccup, hypotension

Question 30

Antihistamines

Answer 30

Diphenhydramine and dimenhydrinate, block histamine at H1 receptor and Ach at M1 receptor for motion sickness and morning sickness

Question 31

Antihistamine Adverse Effects

Answer 31

Sedation, hypotension, confusion, dry mouth, dilated pupils, urinary retention, constipation

Question 32

Anticholinergics

Answer 32

Hyoscine Butylbromide, Dicyclomine block Ach at M1 receptor in motion sickness and morning sickness

Question 33

Anticholinergic Adverse Effects

Answer 33

Tachycardia, blurred vision, dry mouth, constipation, urinary retention

Question 34

Benzidiazepines

Answer 34

Lorazepam, diazepam, Midazolam enhance GABA effects, used as psychotropic, calms the brain, and prevents anticipatory vomiting

Question 35

Benzodiazepine Adverse Effects

Answer 35

Sedation, dry mouth, dizziness, paradoxical agitation

Question 36

Corticosteroids

Answer 36

Dexamethasone, methylprednisolone used in chemotherapy-induced comitign

Question 37

Corticosteroid Adverse Effects

Answer 37

Hyperglycemia, hypertension, osteoporosis, insomnia, intraocular pressure, infection susceptibility, increased appetite, obesity

Question 38

Cannabinoids

Answer 38

Nabilone and Dronabinol used in anticancer-induced vomiting

Question 39

Cannabinoid Adverse Effects

Answer 39

Euphoria, dysphoria, sedation, agitation, hallucination, restlessness, insomnia, irritability, tachycardia, and palpitation

Question 40

Post Operative Vomiting Drugs

Answer 40

Dopamine antagonists, 5HT3 antagonists, and NK1 antagonists acting on CTZ

Question 41

Cytotoxic Drug Induced Vomiting Drugs

Answer 41

5-HT3 antagonists, NK1 antagonists, D2 antagonists, Cannabinoids, and Glucocorticoids acting on CTZ

Question 42

Motion Sickness Drugs

Answer 42

Muscarinic antagonists and antihistamines acting on H1 and M1-M3 receptors in vestibular system