Nausea + Emesis Flashcards
Can vomiting without nausea occur?
Yes, but it is less frequent
Who is more likely to experience vomiting?
Women over men
What does the brainstem “vomiting center” do?
Coordinates vomiting through interactions with cranial nerves 3 + 10
What does the vomit center contain?
M1 receptors
H1 receptors
NK1 receptors
5HT receptors
What does the nucleus tractus solitarius contain?
M1 receptors
H1 receptors
NK1 receptors
5HT receptors
What does the chemoreceptor trigger zone contain?
Chemoreceptors
D2 receptors
NK1 receptors
What are the triggers for vomiting?
Intracranial pressure
Motion sickness
Anxiety
Drugs
Toxins
Chemotherapy
What is serious morning sickness for pregnancy?
Hyperemesis gravidarum
What is the process for treating nausea + vomiting?
- treat complication regardless of cause = replaces salt, H2O
- identify + treat underlying cause
- provide temporary relief for symptoms
What is the problem with anti-emetics?
Oral = if patient is being sick, they aren’t ging to keep them down
Injection = needles aren’t accessible at home + low patient acceptability
What is the best way to treat CINV?
Preventive treatment
= stop being sick in first place
= deceases chance of being sick in future
= able to give higher dose
What are pharmacological treatments for nausea + vomiting?
D2 antagonists
5HT3 antagonists
Antihistamines
Anticholinergics
Pro-motility = metoclopramide
What are antihistamines used to treat?
Montion sickness
PONV
Describe antihistamines
H1 antagonists
What are some examples of antihistamines?
Cyclizine
Diphenhydramine
Meclizine
What are the problems with antihistamines?
Cause CNS depression + sedation
= drowsiness
What are anticholinergics used to treat?
Motion sickness
Describe anticholinergics
Muscarinic acetylcholine receptor antagonists
What are the problems with anticholinergics?
Blockage of parasympathetic ANS
= blurred vision, dry mouth, urinary retention
What is an example of anticholinergic?
Hyoscine
What are dopamine antagonists used to treat?
Drug-induced vomiting + vomiting in GI disorders
How do dopamine antagonists work?
Centrally block D2 receptors in CTZ
Exert prokinetic action on oesophagus, stomach + intestine
What are some examples of dopamine antagonists?
Metoclopramide (low dose)
Chlorpromazine
Haloperidol
What are the problems with dopamine antagonists?
Mimic Parkinson’s disease
When is metoclopramide used at high dose?
Chemo
= at higher level effect serotonin
What does 5HT3 antagonists treat?
PONV
CINV
What are examples of 5HT3 antagonists?
Ondansetron
Granisetron
What are the side effects of 5HT3 antagonists?
Constipation
Headaches
What is an example of prokinetic agent?
Metoclopramide
What do prokinetic agents do?
CTZ anti-dopaminergic activity
What are problems with prokinetic agents?
Obstructed intestine = can cause colic
Increases pressure at lower oesophageal sphincter
What are NK1 antagonists?
Aprepitant
Antagonise NK1 receptors
When are NK1 antagonists used?
Delayed onset nausea associated with chemotherapy
When are cannabinoids used?
For patients undergoing cytotoxic chemotherapy, that is unresponsive to other anti-emetics
How do cannabinoids work?
Decrease vomiting induced by stimulating CTZ