Chapter 4 - Nausea And Labrynth Disorders Flashcards
What is the lifestyle advice associated with nausea and vomiting?
Eat smaller, more frequent meals Remain hydrated (with water, not juice) Eat as tolerated Eat light, bland foods Ginger may help
What is the mechanism of antihistamines in nausea and vomiting?
Block muscarinic receptors
And inhibit cholinergic transmission to the vomiting centre
Give some examples of sedating antihistamines
Chlorphenamine Promethazine Diphenhydramine Cinnarizine Cyclizine
Give some examples of non-sedating antihistamines
Fexofenadine
Cetirizine
Loratadine
Acarvistine
List some antimuscarinic side effects associated with antihistamines
Sedation Dry mouth Constipation Blurred vision Urinary retention
Which antipsychotics can be used in nausea and vomiting?
Chlorpromazine
Prochlorperazine
In palliative care, haloperidol and levopromethazine
When is buccal gem licensed OTC?
Nausea and vomiting associated with previously diagnosed migraine in over 18 year olds
What is the mechanism of phenothiazines in nausea and vomiting?
Block the CTZ
They act centrally
Give examples of prokinetic agents used in nausea and vomiting
Metoclopramide
Domperidone
What is the mechanism of prokinetic agents in nausea and vomiting?
Inhibit the CTZ
Also acts on the GIT
Which antiemetic affects the CTZ and the GI system, metoclopramide or prochlorperazine?
Metoclopramide, therefore it can be used in nausea and vomiting associated with gastric, hepatic and biliary disease
What is the maximum duration of use of metoclopramide?
5 days
Why is the maximum use of metoclopramide 5 days?
Risk of EPSEs
What is the minimum age of metoclopramide?
18 years
Why doesn’t domperidone act centrally?
It doesn’t cross the BBB
At what weight is domperidone unlicensed?
Less than 35kg
Which class of antiemetics shouldn’t be co-prescribed with a prokinetic agent?
Antimuscarinics
This increases antimuscarinic side effects
Concurrent use can lead to confusion in the elderly
The GI effects of prokinetics are antagonised by antimuscarinics
Give examples of 5HT3 receptor antagonists
Onsansetron
Granisetron
When are 5HT3 receptor antagonists used in nausea and vomiting?
Cytotoxic induced nausea and vomiting
Postoperative nausea and vomiting
When is dexamethasone used in nausea and vomiting?
Chemotherapy induced nausea and vomiting
What are the different classes of antiemetics?
Antihistamines Prokinetics 5HT3 receptor antagonists Neurokinin 1-receptor antagonists Dexamethasone Nabilone
Give examples of neurokinin 1-receptor antagonists
Aprepirant
Fosaprepitant
When are neurokinin 1-receptor antagonists used?
Moderately emetogenic chemotherapy
What is nabilone and when is it used?
A synthetic cannabinoid
It is used as add on treatment for chemotherapy induced nausea and vomiting
When does nausea and vomiting in pregnancy usually resolve?
16-20 weeks
Which antiemetics can be used in pregnancy?
Antihistamines e.g. promerhazine, certirizine, chlorphenamine
What is the most effective drug for motion sickness?
Hyoscine
What options are available for motion sickness?
Hyoscine Promethazine Cinnarizine Cyclizine Ginger Acupressure
Which antiemetics should be used in gastric stasis/drug induced nausea and vomiting?
Metoclopramide
Domperidone if EPSEs are a problem
What antiemetic would you give for nausea and vomiting associated with diseases of the inner ear?
Cyclizine
What antiemetic is used for the nausea and vomiting associated with tinnitus, vertigo and hearing loss associated with Ménière’s disease?
Betahistine
Should betahistine be taken with or without food?
With food
What age is cyclizine licensed in?
> 6 years old
It can be given to >1 month old
Don’t give to neonates due to significant antimuscarinic activity
Why is cyclizine cautioned in severe heart failure?
It reduces cardiac output, and therefore increases heart rate
How does alcohol and cyclizine interact?
The effects of alcohol are enhanced
Can patients drive if they have taken nabilone?
Yes, as long it has been taken as prescribed, is within certain limits, and has not impacted the patients driving
It is an offence to drive if nibolone has impaired driving
What are the indications of domperidone?
Nausea and vomiting in adults and children in >12 years
GI pain in palliative care
Neonates with GORD - specialist use only
What is the maximum duration of domperidone and why?
7 days
Due to the risk of CVD effects (arrhythmia)
When are the cardiovascular side effects of domperidone increased?
Over 60 year olds
Daily domperidone doses above 30mg
Patients taking other drugs that increase QT interval prolongation
What is the dose of metoclopramide?
<60kg - 500mcg/kg daily in 3 divided doses
> 60kg - 10mg TDS
When metoclopramide is given by IV injection, how long should it be administered for?
At least 3 minutes
How can the risk of EPSEs be reduced in patients taking metoclopramide?
Short term use (5 days max)
Max 30mg daily
Give the injection over at least 3 mins
When taking metoclopramide, which patient groups are at the highest risk of EPSEs?
Women
The very round or very old
When do EPSEs usually start after taking metoclopramide?
Within 24h
What is the maximum duration of use of ondansetron and why?
5 days
Due to risk of arrhythmias
What is the risk associated with taking ondansetron in pregnancy in the first trimester?
Small risk of cleft lip and/or palate
Which antiemetics are available as a patch?
Hyoscine - change every 72 hours
Granisetron - change every 10 days
What are the indications of hyoscine?
Motion sickness
Excess secretions in palliative care
Bowel colic pain in palliative care
Hypersalivation due to clozapine
How is the hyoscine patch used?
Apply behind the ear 5-6 hours before the journey
Change patch after 72 hours if needed
The patch can be cut if required
What are the brand names of hyoscine?
Patch - scopoderm
Tablets - keels, joyrides
