Antiemetics

Question 1

What class of drug is Metoclopramide?

Answer 1

Dopamine 2 receptor antagonist

Question 2

metoclopramide is also involved with serotonin

Answer 2

5HT4 (increases peristalsis, increase smooth muscle contraction, increase gut secretion) AGONIST
5HT3 (causes N+V) ANTAGONIST

Question 3

What are the common indications for Metoclopramide?

Answer 3

Post operative nausea, vomiting and certain digestive disorders.

Question 4

What is the mechanism of action of Metoclopramide?

Answer 4

Central dopamine antagonist
Blocks messages from the CTZ (chemoreceptor trigger zone) and the vomiting centre
Peripheral cholinergic agonist. Increases tone and motility of the stomach and intestines, speeding up digestion (5HT4) - why it is good for GORD

Question 5

why is metocloperamide known as a pro kinetic drug

Answer 5

• increases the tone of the LOS and causes gastric emptying and increases the gut motility

Question 6

What are the adverse effects of Metoclopramide?

Answer 6

Depression, diarrhoea, drowsiness, hypotension and galactorrhoea

Question 7

What are the drug-drug interactions of Metoclopramide?

Answer 7

Anti-psychotic drugs, dopamine agonists
- can give parkinsonian effects as it can cross the BBB

Question 8

if a patient is on metocloperamide and is suffering from parkinsonian effects what other medication could you switch them too?

Answer 8

Domperidone
It does not cross the BBB and is metabolised peripherally

Question 9

How can you remember Metoclopramide?

Answer 9

Question 10

What class of drug is Ondansetron?

Answer 10

Serotonin antagonist
5Ht3 receptor antagonist

Question 11

What are the common indications of Ondansetron?

Answer 11

To prevent nausea and vomiting in chemotherapy

Question 12

What is the mechanism of action of Ondansetron?

Answer 12

Blocks (vagal) afferent signals from the gut to the CTZ
Peripherally reduces GI motility and reduces GI secretions

Question 13

What are the adverse effects of Ondansetron?

Answer 13

Constipation, headache, elevated liver enzymes
Extra-pyramidal effects- dystonia, parkinsonism

Question 14

What are the warnings with Ondansetron?

Answer 14

Subacute abdominal obstruction, susceptible to long QT

Question 15

What are the drug-drug interactions of Ondansetron?

Answer 15

Serotonin agonists, drugs that prolong the QT interval (Tramadol)

Question 16

How can you remember Ondansetron?

Answer 16

Question 17

what class is hyoscine hydrobromide

Answer 17

muscarinic receptor blocker at the vestibular nuclei
blocks acetylcholine

Question 18

how does hyoscine hydrobromide work

Answer 18

competitive blockade of the myscarinic acetylcholine receptors in the CTZ

Question 19

what are some side effects of hyoscine hydrobromide

Answer 19

glaucoma and dry mouth as it blocks the muscarinic receptors

Question 20

what is a condition in which you shouldn’t prescribe hyoscine hydrobromide

Answer 20

myasthenia graves as it blocks the muscarinic receptors

Question 21

what class of drug is ranitidine

Answer 21

Anti histamine (H2)

Question 22

how does Ranitidine work

Answer 22

It is a competitive reversible inhibitor of histamine in the gastric parietal cells
= stops the gastric acid secretion and reduces H conc

Question 23

when would you prescribe ranitidine

Answer 23

when someone has high stomach acid

Question 24

what class of drug is cyclizine

Answer 24

H1 receptor blocker

Question 25

how does cyclizine work

Answer 25

acts at the vestibular nuclei and inhibits histaminergic signals from vestibular system to CTZ

Question 26

What are some uses of cyclizine

Answer 26

motion sickness

Question 27

what is promethazine used for

Answer 27

morning sickness

Question 28

what is the first line medication for bowel obstruction

Answer 28

cyclizine then give dexamethasone

Question 29

what are two anti-emetic drugs that can be given to pregnant women who are feeling morning sickness

Answer 29

promethazine and prochlorperazine

Question 30

what class of drug is haloperidol

Answer 30

D2 receptor antagonist

Question 31

how does haloperidol work

Answer 31

acts on the CTZ causes the LOS to close increases gastric contraction and reduces the pylorus tone so it opens

Question 32

haloperidol is an anti-emetic but it can also be classed into what other drug type

Answer 32

anti-psychotic can be used to treat schizophrenia

Question 33

what is an ADR of haloperidol

Answer 33

it is a D2 antagonist so can cause prolonged QT DO NOT give to someone who has Parkinson's

Question 34

what are some side effects of haloperidol

Answer 34

sedation hypotension

Question 35

Chlorpromazine and levomepromazine are both from which drug class

Answer 35

D2 receptor antagonist

Question 36

Dexamethasone is what class of drug

Answer 36

corticosteroid

Question 37

when is dexamethasone used

Answer 37

in chemo when people feel Sick and nauseous GIVE ondansetron too of not strong enough

Question 38

what is a side effect of dexamethasone

Answer 38

HIGH SUGAR all steroids increase sugar levels increased weight

Question 39

Aprepitant and fosaprepitant are class of what drug

Answer 39

neurokinin-1 receptor antagonist

Question 40

how does Aprepitant work

Answer 40

prevents the action of substance P at CTZ and peripheral nerves boosts the effect of the 5HT3 receptor antagonist

Question 41

what other drug class can aprepitant be in

Answer 41

- anti anxiety anti-psychotic