Nausea & vomiting Flashcards
What are the 7 groups of antiemetic drugs?
- Serotonin 5-HT3 antagonists
- Corticosteroids
- Neurokinin receptor antagonists
- Dopamine receptor antagonists
- Muscarinic receptor antagonists
- H1 histamine receptor antihistamines
- Benzodiazepines
What are the 4 sites that an trigger the vomiting reflex?
- Chemoreceptor trigger zone in the brain
- GIT
- Vestibular system
- Higher centres in the CNS
What is the treatment for chemotherapy regiment with LOW emetogenic risk?
Serotinin 5-HT3 receptor antagonist (first-line) OR
Dexamethasone OR
Dopamine D2 receptor antagonist
Name 2 examples of serotonin 5-HT3 antagonists
Ondansetron
Granisetron
Granisetron longer half-life; better for cancer patients
MOA of ondansetron?
Act at 5-HT3 receptors primarily in the GIT
Which antiemetics increase risk of cardiac arrhythmias?
Serotonin 5-HT3 antagonists & droperidol
May prolong QT interval
What group of patients is ondansetron contraindicated in?
Cardiac abnormalities
Early pregnancy
Patients on drugs that prolong QT interval
Ondansetron increases risk of orofacial malformations in early pregnancy
Fluoroquinolones, macrolides, azoles, antidepressants, anti-arrhythmia medications
What can 5-HT3 antagonists be combined with to increase antiemetic effect?
5HT3 antagonist + corticosteroid (dexamethasone) + NK1-receptor antagonist
When is ondansetron given to prevent N&V in patients undergoing chemo?
30min before chemo; IV
Name an example of a D2 receptor antagonist
Meteoclopramide
MOA of metoclopramide?
Blocks dopamine D2-receptors in the CTZ
Chemoreceptor trigger zone
What are the side-effects of long-term metoclopramide use?
Irreversible tardive dyskinesia
Wrong movements like twitching of the face
Which antiemetic causes Parkinsonian symptoms?
Metoclopramide
Adverse effects of metoclopromide?
Parkinsonian symptoms
Irreversible tardive dyskinesia
Elevated prolactin
Elevated prolactin causes manboobs, impotence, galactorrhea
What is the treatment for chemotherapy regiment with HIGH emetogenic risk?
5-HT3 receptor antagonist + corticosteroid (dexamethasone) + neurokinin 1-receptor antagonist