Antiemesis Flashcards
Four drugs that can bring about emesis.
Chemo
Opioids
Digoxin
GA
The Vomiting Centre receives its input from which three places?
- The chemoreceptor trigger zone (CTZ)
- Cerebral Cortex
- Inner ear.
Three things can make us wanna puke. Toxins, motion sickness and interestingly, things that subjectively disgust us.
What three places feed into the vomiting centre?
- The CTZ
- The inner ear
- The cerebral cortex
What four receptors can be targets for antagonist therapy in anti-emesis?
H1
5HT3
DA
mAChR
Why is there no universal antiemesis drug?
Because none would target all of the relevant receptors.
Is antiemetic therapy tyically useful once emesis has set in?
No, they’re characteristically only really reliable for prophylaxis of nausea and emesis.
CINV is?
CHEMOTHERAPY-induced nausea and vomiting.
NVP is?
Nausea and Vomiting in PREGNANCY
What antipsychotics (anti-DA) are used in anti-emesis?
Horse pushing a pram making noise with his horseshoes.
I’m all for drowning Perez Hilton in chlorine.
This dom perignon champagne is overated. I’m still gonna drink every last drop.
Prochlorperazine
Metoclopramide
Domperidone
Droperidol.
Where does antiemetic DA-block occur?
CTZ only.
Where does antiemetic DA-block occur?
CTZ only.
It’s usually phenothiazine antipsychotics that are used for antiemesis. What side effect do they normally have apart form the usual muscle stuff?
Sedation.
What does peripheral D2 antagonism do to help antiemesis?
Lowers oesophageal sphinctre tone
Increases gastric emptying
Domperidone - cons?
Weak (has to be taken in combination)
Rare EPS
Where does the anticholinergic block act to prevent vomiting?
WHere is it thereby useful?
Vestibular nuclei
Motion sickness
What is the name of the anticholinergic antiemetic?
Being chased by a hyena would be good to stop vomiting.
Hyoscine (aka scopolamine).
Hyoscine (aka scopolamine) also acts non-specifically on some H1 receptors. What side effect does this cause?
Sedation.
Where do we find emetic mAChR adn H1 receptors in teh CNS?
vestibular nuclei
solitary tract’s nucleus
What are the best antiemetics for CINV?
5HT3 blockers.
What are the antihistamines? Antihistamines are used for morning and motion sickness.
I’m sitting here pregnant and nauseous wishing all men would die so I can just get back to my meth habit like I was smoking at prom where he knocked me up.
Dimenhydropinate
Promethazine.
What are the antihistamines?
Dimenhydroptinate
Promethazine
Could I use dimenhydroptinate or promethazine to drive to sussex if I took it half and hour before?
Yes - 4-6 hours duration.
But you shouldn’t because it causes sedation and impairs performance.
Because the glowing ball of specialness in an annoying mother is so fucking precious, what can we give to the annoying woman to shut her up?
Ginger or VitB6 (aka pyridoxine)
What is the only antihistamine we can give to a pregnant woman?
doxylamine
You’d really need muscles to pull a scollop off a rock or fight a hyena. What’s the only anticholinergic mentioned in this lecture?
hyoscine/scolopamine
If someone’s getting REALLY hardcore chemo, what’s the big-gun combination of four antiemetics?
Aprepitant + glucocorticoid + 5HT antagonist + dexamethasone?
For antiemesis, what’s the glucocorticoid you need to remember?
Hopefully you have enough dex to get you in the zone for this stupid glucocorticodi.
Dexamethasone.
Antiemetic glucocorticoid?
Dexamethasone.
Why are DA antagonists ineffective for motion sickess?
Because the vestibular nucleus has no DA receptors. Those are only in the CTZ (where they hang out with seratonin receptors).
What does aprepitant do?
The think I like about camping is peeing outside.
Blocks substance P, NK receptors in the CTZ.
Why is aprepitant unlikely to have similar side effects to the other drugs?
No affinity for any of their receptors.
