nausea and vomiting Flashcards
what is emesis?
the process of vomiting
what are the stages of emesis?
nausea
retching
vomiting
forceful expulsion of gastirc contents
what is an emetic?
an agent which causes vomiting
what is an anti-emetic?
something that prevents vomiting
how does something trigger vomiting?
stimulus is sent to the vestibular centre, GI tract and the chemoreceptor trigger zone.
the greater the frequency of stimulation the faster it will reach the threshold and therefore causing vomiting.
what might cause vomiting?
- abdominal conditions
- gastritis
- metabolic issues
- cerebral disease
- ear disorders
- malignancy
- pain
- psyhogeneic
- drugs
- alcohol
what are risk factors for vomoting?
gender
face
but very much down to indivudual variation and environmental factors
what are the 5 neurotransmitters involved with nausea and vomiting/
- acetylcholine
- dopamine
- serotonin
- histamine
- substance p
which neurotransmitters affect the vestibular centre/
histamine
acetylcholine
what neurotransmitters affect the CTZ?
- serotonin
- dopamine
- substance P
what neurotransmitters affect the vomiting centre?
– Histamine
– Acetylcholine
– Substance P (NK1)
– Serotonin (5-HT2/3)
which neurotransmitters affect the vomiting centre?
– Histamine – Acetylcholine – Substance P (NK1) – Dopamine – Serotonin (5-HT3)
which neurotransmitter affect the vomiting centre through the vagus nerve?
- Acetylcholine
- Dopamine
- Serotonin (5-HT3
what do you need to consider when deciding how to treat nausea and vomiting?
- 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
when would you use antihistamines?
motion sickness
irritants in the stomach
where do the antihistamines mainly work?
- vestibular centre
- GI tract
what are the two major examples used of antihistamines?
• Cinnarizine – Motion sickness • Promethazine – Motion sickness – General N+V (gastric irritation) – Morning sickness (last resort – not licensed)
when would you use anticholingerics?
– Motion sickness
– Irritants in stomach
what do anticholingerics mainly work on?
• Acetylcholine (primarily)
– vestibular centre
– GI tract
what are the two major examples of anticholingerics?
• Hyoscine – Motion sickness – Available in oral or transdermal formulations – So if N&V is making patient unable to take oral route this is good – Effects gut motility and needs to be careful with MF – Can cause N&V • Cyclizine – Motion sickness, post op N&V – Vestibular disorders – Palliative care uses – N+V of known cause – Be cautious in epilepsy and glaucoma
when would you use 5-HT3 antagonists?
– Post operative nausea and vomiting
– Chemotherapy induced nausea and vomiting
– Radiotherapy induced nausea and vomiting
where do 5-HT3 antagonists affect upon?
– CTZ
– GI tract – good for chemotherapy induced N&V and post op
what are examples of 5-hT3 antagonists?
• Ondansetron can be patch – PONV – CINV – RINV – Every patient over age of 65 who has ondansetron infusion needs to have it atleast over 15 mins to reduce the side effects profile. – Cause constipation and also headaches • Palonosetron – i/v long action – CINV • Granisetron – PONV – CINV – RINV
what are d2 antagonists used for?
– Post operative nausea and vomiting
– Chemotherapy induced nausea and vomiting
– Radiotherapy induced nausea and vomiting
where do d2 antagonists work upon
– CTZ
– Can be present in the GI tract but not sure if its significant for N&V
what are examples of d2 antagonists?
• Metoclopramide – PONV – CINV – RINV – Migraine – MHRA alerts – metoclopramide can be given i/v or orally. It is contraindicated in Parkinson's, it crosses the BBB and it causes EPSPs symptoms. Limited the dose to 10mg TDS as these side effects can be nonreversible, not to be used for more then 5-7 days. • Domperidone – Nausea and vomiting – Domperidone doesn’t cause the Parkinsonal symptoms as it doesn’t cros Bbb so it is more often used but it can cause cardiac toxicity. • Haloperidol – CINV – Haloperidol is usually used for non responsive N&V and you can use it from does to 500mcg to 2mg. But it can prolong QT so not used for all cardiac conditions
when are NK1 antagonists used?
– Chemotherapy induced nausea and vomiting
what do NK1 antagonists work upon?
– CTZ
– Present in GIT tract butnot sure on its significance
what are examples of NK1 antagonists/
• Aprepitant – Oral, 3 day course • Fosapreitant – IV, single dose • Netupitant – Oral, single dose, combined with palonosetron • Rolapitant – Oral, single dose
when would you use cannibiods/
• Used when no other drug effective – nothing else has worked
what are the side effects of cannabinoids?
- Side effects (common) – drowsiness, dizziness, dry mouth,
* Side effects (rare) - mood changes, postural hypotension, hallucinations, psychotic reactions
when would you use steroids?
• Used for CINV at supraphysiological doses – doses higher then the normal circulating dose you would expect in the body
what is the cannaboinoid used?
nabilone
what is the name of the steroid sued to treat?
dexamethasone
when would use levomepromazine?
– Dirty drug – acts on a lot of different neurotransmitters. But this could be very useful for certain N&V. it is usually used 2nd line
what might you use in pregnancy?
- Metoclopramide
- Prochlorperazine
- Cyclizine
- Promethazine
- Ondasetron (hyperemesis gravidarum)
what are the most recognisable factors of PONV?
- Being female
- Being a non smoker
- History of PONV
- Use of peri-operative opioid analgesia
what do you need to pre surgery?
- assess the potential surgery and whcih anaesthic is best
- patient factors calculate
- counsel patient
- give anti-emetic
- avoid feeding for a few hours pre and post
- NEED TO PREVENT AS HARD TO STOP ONCE STARTED
what are the risk factors for chemotherapy NV?
– Female gender – Age < 30 – Pre-existing N+V – Poor control with prior treatment – History of N+V (Motion sickness/in pregnancy) – Anxiety
