8.3 Anti-emetics Flashcards

1
Q

What is Emesis and give a definition

Give two potential stimuli

A

Emesis = vomiting

It is a physiologic response to irritating and potentially harmful substances in blood or gut

May be due to excessive vestibular stimulation or psychological stimuli

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2
Q

Emesis involves co-ordination of _______, _______, _______contractions controlled by the vomiting center

A

pharyngeal,GI, abdominal wall

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3
Q

Where is the vomiting centre located

A

In the medulla

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4
Q

Give some examples of centres which influence the vomiting centre

Which have positive/negative effects?

A

Most are positive influences from gut, vestibular apparatus, solitary tract and chemoreceptor trigger zone (CTZ)

Cerebral cortex can be positive or negative

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5
Q

Give examples of receptor found in the following:

  1. Chemoreceptor Trigger Zone (CTZ)
  2. Solitary Tract
  3. Gut
  4. Vestibular Apparatus
A

Chemoreceptor Trigger Zone (CTZ): D2, M1, 5-HT3

Solitary Tract: D2, M1, 5-HT3, H1, NK1

Gut: 5-HT3

Vestibular Apparatus: M1, H1

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6
Q

Give the 6 classes of Anti-Emetics

A
  • dopamineinhibitors
  • serotonininhibitors
  • anti-histamines
  • phenothiazine
  • anti-cholinergics
  • neurokinin-1 inhibitors
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7
Q

Give 2 examples of dopamine Inhibitors + where each acts

A

metoclopramide and domperidone

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8
Q

Give the MoA of dopamine inhibitors

A

Binds to receptors to inhibit action of dopamine

CTZ = rich in D2 receptors

Prokinetic effect in GI

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9
Q

Give 2 side effects of dopamine inhibitors and explain why each occurs

A

Diarrhoea: b/c it is prokinetic

Extrapyramidal side effects because of its dopaminergic effect (normally metoclopramide)

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10
Q

Give 2 contraindications of dopamine inhibitors

A

Obstruction

Perforation

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11
Q

Give an example of a serotonin Inhibitor + where it acts

A

ondansetron

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13
Q

Give the MoA of serotonin inhibitors

A

Binds to receptors to inhibit action of serotonin

CTZ – rich in 5-HT3 receptors

Serotonin released by gut in response to emetogenic stimuli

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14
Q

Give 3 side effects of serotonin inhibitors and explain why each occurs

A

Constipation, Diarrhoea, Headache

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15
Q

Give a contraindication of serotonin inhibitors and when it should be completly avoided

A

Risk of QT prolongation

Avoid with SSRI, antipsychotics, quinine

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16
Q

Give 2 examples of Anti-histamines + where they act

A

cyclizine and promethazine

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17
Q

Give the MoA of Anti-histamines

A

Blocks H1, M1 receptors between vestibular system, vomiting center

18
Q

Give 2 side effects of Anti-histamines

A

Drowsiness and Anti-cholinergic effects

19
Q

Give 2 contraindications of Anti-histamines

A

Prostatic hypertrophy

Hepatic encephalopathy

20
Q

Give 2 examples of phenothiazines

A

prochlorperazine and chlorpromazine

21
Q

Give the MoA of Phenothiazines

A

Blocks D2 receptor in CTZ, gut and to a lesser extent, blocks H1, M1 receptors in CTZ, vestibular apparatus

22
Q

Give 4 side effects of Phenothiazines

A

Drowsiness, postural hypotension, extrapyramidal side effects, anti-cholinergic side effects

23
Q

What is the biggest risk with Phenothiazine and therfore when should you avoid it?

A

Risk of QT prolongation

Avoid with quinine, SSRIs, anti- psychotics

24
Q

Give an example of a Anti-cholinergic

A

hyoscine hydrobromide

25
Q

Give the MoA of Anti-cholinergics

A

Blocks M1 receptors

26
Q

Give the side effects of Anti-cholinergics

A

Anti-cholinergic side effects

27
Q

Give a contraindication of Anti-cholinergics

A

GI obstruction

28
Q

Give an example of a Neurokinin 1 inhibitor

A

aprepitant

29
Q

Give the MoA of Neurokinin 1 inhibitors

A

Blocks neurokinin receptor

30
Q

Give 3 side effects of Neurokinin 1 inhibitors

A

headache, GI discomfort, constipation

31
Q

Give a drug given for Hyperemesis short term

A

antihistamine, phenothiazine, dopamine inhibitor

32
Q

Give an antiemetic that is given post op?

Give 2 factors that drug choice is determined by

A

seroton ininhibitors, phenothiazine, anti-histamine

Depends on anaesthetic, type and duration of surgery, female, non-smoker, intra-operative opioid use

33
Q

Which antiemetic is given for chemotherapy

A

Seroton ininhibitor

34
Q

Give a antiemetic given for opioid Induced hypermesis

A

Dopamine inhibitors