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The Patient Y3 Semester 2 > Nausea and Vomiting > Flashcards

Nausea and Vomiting Flashcards

1
Q

What is emesis?

A

The process or act of vomiting’

  • Protective physiological mechanism E.g. to expel an ingested toxin or poison

Happens in stages

  • Nausea
  • Retching
  • Vomiting
  • -> Forceful expulsion of gastric contents
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2
Q

Pathophysiology:

A

Stimulus (visceral, vestibular, CTZ)–> CTZ (Chemoreceptor trigger zone) –> Vomiting centre

Vomiting centre – within BBB

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3
Q

Causes of N+V:

A

Abdominal conditions –>
Carcinoma, peritonitis, Obstruction, infection

Gastritis –> Alcoholic or drug-related

Metabolic –> Uraemia,↑glucose, ↑bilirubin, ↑calcium

Cerebral disease –> Tumour, abscess, meningitis

Inner ear disorders –> Infection, Menière’s, motion sickness

Malignancy –> Disease, drugs, radiation

Pain –> Myocardial infarction, Post –operative

Psychogenic –> Anorexia, anticipatory, mental association

Drugs –> Anaesthetics, opiates, oestrogens, levodopa

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4
Q

Risk factors’ and the dynamic threshold:

A

Risk factors

  • More clearly defined for specific types e.g. CINV
  • Gender
  • Race

Threshold for nausea and vomiting can change

  • Individual variation
  • Environmental factors
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5
Q

Neurotransmitters in N+V?

A
  • Acetylcholine
  • Dopamine
  • Serotonin
  • Histamine
  • Substance P
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6
Q

Which neurotransmitters where?

A

Vestibular centre

  • Histamine
  • Acetylcholine

CTZ

  • Serotonin (5-HT3)
  • Dopamine
  • Substance P (NK1)

Vomiting Centre

  • Histamine
  • Acetylcholine
  • Substance P (NK1)
  • Serotonin (5-HT2/3)

GI tract

  • Histamine
  • Acetylcholine
  • Substance P (NK1)
  • Dopamine
  • Serotonin (5-HT3)

Via vagus nerve

  • Acetylcholine
  • Dopamine
  • Serotonin (5-HT3)
  • Higher cortical centres
  • Histamine
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7
Q

How to treat N+V?

A
  • Identify the possible cause(s) of the nausea and vomiting.
  • Choose a drug that will act on the pathway
  • Give the appropriate dose, frequency and route.
  • Monitor effect.
  • If ineffective change to alternative agent.
  • Address other contributing factors
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8
Q

Antihistamines for N+V:

A

Histamine (primarily)

  • vestibular centre
  • GI tract

Useful for:

  • Motion sickness
  • irritants in stomach

Drugs:
Cinnarizine
–> Motion sickness

Promethazine (sedating)

  • Motion sickness
  • General N+V (gastric irritation)
  • Morning sickness (last resort – not licensed)
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9
Q

Anticholinergics for N+V:

A

Acetylcholine (primarily)

  • vestibular centre
  • GI tract

Useful for:

  • Motion sickness
  • Irritants in stomach

Drugs:
Hyoscine
- Motion sickness
- Available in oral or transdermal formulations

Cyclizine

  • Motion sickness
  • Vestibular disorders
  • N+V of known cause
  • Used in chemo, use with caution in epilepsy and glaucoma
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10
Q

5-HT3 antagonists for N+V:

A

Serotonin (NT of choice)

  • CTZ
  • GI tract

Useful for:

  • Post operative nausea and vomiting
  • Chemotherapy induced nausea and vomiting (as chemo induces vomiting via GI tract)
  • Radiotherapy induced nausea and vomiting

Options:

Ondansetron – at least 15 mins infuse

  • PONV
  • CINV
  • RINV

Palonosetron (iv mostly)
- CINV

Granisetron

  • PONV
  • CINV
  • RINV
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11
Q

MHRA Alert for 5-HT3 antagonists:

A

MHRA Alert QT prolongation

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12
Q

D2 Antagonists for N+V:

A

Dopamine
- Primarily CTZ

Useful for:

  • Post operative nausea and vomiting
  • Chemotherapy induced nausea and vomiting
  • Radiotherapy induced nausea and vomiting
Options
Metoclopramide – oral or iv
- PONV
- CINV
- RINV
- Migraine

Domperidone

  • Nausea and vomiting
  • Doesn’t cross BBB

Haloperidol
- CINV

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13
Q

NK1 Antagonists in N+V:

A 
Substance P (NK1)
- CTZ

Useful for:
- Only Chemotherapy induced nausea and vomiting

Options:
Aprepitant
- Oral, 3 day course.

Fosapreitant
- IV, single dose. Useful for upper gi and head and neck cancer patients who are struggling to swallow

Netupitant
- Oral, single dose, combined with palonosetron

Rolapitant
- Oral, single dose (favoured drug)

All show efficacy of 120 hours

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14
Q

Cannabinoids in N+V:

A
  • Nabilone
  • Orally active
  • Acts on CTZ, via opioid receptors
    Used when no other drug effective

Side effects (common) – drowsiness, dizziness, dry mouth,

Side effects (rare) - mood changes, postural hypotension, hallucinations, psychotic reactions

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15
Q

Steroids in N+V:

A
  • Dexamethasone
  • Used for CINV at supraphysiological doses (higher than expected)
  • Unclear mechanism
  • Usually used in combination with other agents
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16
Q

What is Levomeprozamine:

A

Levomepromazine (unlicenced)

  • Dirty drug
  • Useful
Acts on:
Histamine
Serotonin
Acetylcholine
Dopamine

Can be quite sedating

17
Q

Drugs used in pregnancy:

A
  • Metoclopramide
  • Prochlorperazine
  • Cyclizine
  • Promethazine
  • Ondasetron (hyperemesis gravidarum)
18
Q

Overall incidence of PONV is reported to be around 30% and the most recognised factors are:

A
  • Being female
  • Being a non smoker
  • History of PONV
  • Use of peri-operative opioid analgesia

Other factors include

  • Age
  • Obesity
  • Delayed gastric emptying – lack of gut motility
  • Surgical factors
  • Anaesthesia
19
Q

PONV procedure:

A
  • Assess the potential of the surgery, anaesthetic agent to cause vomiting
  • Assess the patient for factors contributing to post-op nausea
  • Counsel patient
  • Give anti-emetic agent with anaesthetic agent or immediately on recovery.
  • Avoid early mobilisation/feeding
  • Give appropriate pain control with an anti-emetic.
  • Patients identified as low risk do not usually need prophylaxis.
    -Treat dehydration and pain in all patients suffering from nausea and vomiting.
  • Patients at moderate risk should be considered for monotherapy
  • High risk patients can require several prophylactic agents with different pharmacological actions
20
Q

What is CINV?

A

Chemotherapy induced nausea and vomiting

21
Q

What are the 5 types of CINV?

A

Acute - within 24 hours of chemo admin

Delayed- 48-72 hours

Breakthrough - occurs within 5 days

Refractory - occurs in subsequent chemotherapy cycles

Anticipatory - N+V that is triggered by sensory stimuli associated with chemotherapy administration

22
Q

CINV Chemotherapy induced nausea and vomiting risk factors:

A
  • Female gender
  • Age < 30
  • Pre-existing N+V
  • Poor control with prior treatment
  • History of N+V (Motion sickness/in pregnancy)
    Anxiety
23
Q

CINV protective factors:

A

History of high alcohol intake, substance misuse or smoking

24
Q

Refractory and anticipatory N+V treatment:

A

Refractory

  • Levomepromazine
  • Olanzapine
  • Haloperidol
  • Nabilone

Anticipatory
- Lorazepam

25
Q

OTC N+V relief:

A 
Antihistamines
- Cinnarizine
- Cyclizine
- Promethazine
Hyoscine hydrobromide

Antacid–like

  • Rennies
  • Pepto-bismol
  • Enos/Andrews – Sodium Bicarbonate
  • H2 antagonists
  • Proton pump inhibitor (omeprazole)
26
Q

Migraine treatment:

A
  • Phenothiazine and antihistamine antiemetics
  • Buccal prochlorperazine is licensed for migraine
  • -> P
  • -> A single dose should be given at the onset of symptoms

Metoclopramide/domperidone
- Caution due to potential side effects

27
Q

Points to remember

A
  • Vomiting can cause biochemical abnormalities and dehydration
  • Refer if severe, concurrent fever or diarrhoea, faecal, coffee ground
  • Consider route/form

The Patient Y3 Semester 2 (21 decks)

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