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