Anti-Nausa and Anti-Emetic Drugs Flashcards
What are the serotonin receptor antagonists?
Dolasetron
Granisetron
Ondansetron
Palonosetron
What is the common suffix for serotonin receptor antagonists?
-setron
What specific receptors do serotonin antagonists act on?
5-HT3
What is the is the downstream effect of serotonin receptor inhibition?
block serotonin type 3 receptors at vagal nerve terminals and block signal transmission to chemoreceptor trigger zone
What is the potential toxic effect of 5HT3 antagonists?
dose-dependent QT prolongation
*Dolasetron has highest risk
What 5HT3 antagonists would you use for delayed chemotherapy induced N/V as a single dose?
Palonosetron
sustained-release formulation of Granisetron
What are the neurokinin receptor antagonists?
Aprepitant Fosaprepitant Netupitant Fosnetupitant Rolapitant
What does the prefix “fos” represent?
Pro-drug
What is the common suffix of neurokinin receptor antagonists?
-pitant
What specific receptors do neurokinin antagonists act on?
NK1
What is the anti-emetic classification of 5HT3 antagonists?
strong anti-emetics
What is the anti-emetic classification of NK1 antagonists?
moderate anti-emetics
What is the downstream effect of NK1 antagonists?
blockade of NK1 receptors in the chemoreceptor trigger zone
blockade of NK1 receptors on vagal terminals in gut
Are NK1 antagonists used for chemotherapy induced N/V?
Yes but they are most effective in combination with 5HT3 antagonists and glucocorticoid
What is given for prophylaxis post-op N/V?
aprepitant
What are the possible adverse effects of NK1 antagonists?
GI (dyspepsia/constipation/diarrhea)
CNS (dizziness/fatigue/somnolence)
What do you need to check before giving NK1 antagonists?
mild CYP450 inhibition so need to check for drug interactions
What are the histamine receptor antagonists?
Diphenhydramine Dimenhydrinate Hydroxyzine Promethazine Meclizine Cyclizine Doxylamine + B6
What is the anti-emetic classification of histamine receptor antagonists?
weak anti-emetics
What specific receptors do histamine antagonists act on?
H1
What is the downstream effects of H1 antagonists?
blockade of H1 receptors in vomiting center and vestibular system
anticholinergic properties at the level of the chemoreceptor trigger zone
What are the adverse effects of H1 antagonists?
*classic anticholinergic effects* drowsiness dry mouth constipation urinary retention blurred vision
What is given for N/V of pregnancy?
doxylamine + B6
What are given for motion sickness/vertigo?
meclizine
cyclazine
scopolamine
What are the dopamine receptor antagonists?
chlorpromazine
perphenazine
prochlorperazine
metoclopramide
What is the anti-emetic classification of dopamine antagonists?
weak to moderate anti-emetics
What specific receptors do dopamine antagonists act on?
D2
What is the downstream effect of D2 antagonists?
blockade of D2 in CTZ
varying levels of anticholinergic properties
What is special about the downstream effect of metoclopramide?
also stimulates ACh actions in GI
enhances GI motility and increases LES tone
What are the adverse effects D2 antagonists?
*classic anticholinergic effects* drowsiness dry mouth constipation urinary retention blurred vision
arrythmias and extrapyramidal SE’s are possible with large doses!
What is used for gastroparesis/dysmotility?
meoclopramide
What is the muscarinic receptor antagonist?
scopolamine
What is the anti-emetic classification of muscarinic receptor antagonists?
weak anti-emetic
How is scopolamine administered?
transdermal via 72 hr patch
What specific receptors do muscarinic antagonists act on?
M1
What is the downstream effect of M1 receptors?
block of Ach-stimulated muscarinic receptors in neural pathways from the vestibular nuclei and reticular formation
What are the adverse effects M1 antagonists?
*classic anticholinergic effects* drowsiness dry mouth constipation urinary retention blurred vision
What can be given for end-of-life care for excessive secretions?
scopolamine
What are the cannabinoid receptor agonists?
Dronabinol
Nabilone
What is the antiemetic classification of cannabinoid receptor agonists?
strong anti-emetic
What is the downstream effect of CB agonists?
Stimulates CB1 and CB2 receptors in the CTZ
Exert signal transduction effects through GPCRs resulting in decreased excitability of neurons – minimizes 5HT3 release from vagal nerve
When would you use CB agonists?
Chemo induced N/V for treatment resistant scenarios
What is another beneficial effect of CB agonists?
appetite stimulation
What are some “adverse” effects of CB agonists?
Euphoria ;) Vertigo Sedation Impaired cognition/memory Altered perception of reality/hallucinations Xerstomia Increased HR/BP
What is the classic high-emetogenic regimen?
NK1 antagonist
5HT3 antagonist
Corticosteroid (dexamethasone)
may increased to 4 drug regimen with D2 antagonist or CB agonist
What is the classic moderate-emetogenic regimen?
5HT3 antagonist
corticosteroid (dexamethasone)
may increased to 3 drug regiment with NK1 antagonist or CB agonist
What is the classic low-emetogenic regimen?
corticosteroid OR
5HT3 antagonist OR
metoclopramide OR
prochlorperazine
What is the classic minimal-emetogenic regimen?
No prophylaxis therapy recommended
What is the stepped-therapy for pregnancy N/V?
- B6 OR H1 antagonist + B6 OR 5HT3 antagonist
- D2 antagonist
- Steroid or different D2 antagonist