Antiemetic Drugs Flashcards
What are the seven types of Antiemetic Drugs?
Serotonin (5HT3) Antagonists, Anticholinergics, Neurokinin Receptor 1 (NK1) Antagonists, Anithistamines (H1), Dopamine (D2) receptor antagonists, Cannabinoids, Corticosteroids
What are the four Serotonin (5HT3) drugs?
Dolasetron, Granisetron, Ondansetron, Palonosetron
What is the MOA of Serotonin (5HT3) Antagonists?
Blockage of peripheral 5HT3 receptors on primary afferent. Also acts in CTZ (chemoreceptive trigger zone) and VC (vomiting center)
What is the therapeutic use for Serotonin (5HT3) Antagonists?
Drugs of choice for preventing and inhibiting chemotherapy-induced N/V, Prevent acute phase (less than 24 hours after infusion) if given 30 min prior to chemo. Also used post op and post radiation.
What are the side effects of Serotonin (5HT3) Antagonists?
Well tolerated. Excellent safety profiles. Esp. compared to Alosetron. Most SE are transient (constipation, dizziness, HA). Small QT elongation.
What drug is truly effective for prevention of chemo emesis (esp. caused by Cisplatin)?
Ondansetron
What are Serotonin (5HT3) Antagonists NO effective for?
Not as effective at delayed (2-5 days) of chemo or for motion sickness.
What Anticholinergic should you know?
Scopolamine
What is the MOA of Anticholinergics?
Muscarinic and cholinergic receptor antagonists. Esp. at cerebellum. Widely distributed in CNS.
What is the therapeutic use of Scopolamine?
Motion sickness (most effective)
What are the side effects of Scopolamine?
Given as transdermal patch to dec. systemic side effects compared to oral.
What Neurokinin Receptor 1 (NK1) Antagonists should you know?
Aprepitant (oral), Fosaprepitant (IV)
What is the MOA for NK1 Antagonists?
Antagonize substance P receptor. Central higher order center - NK1 receptors.
What is the therapeutic use of NK1 Antagonists?
Chemotherapy induced N/V. Given in combo with 5HT3 receptor antagonists and dexamethasone.
What are the side effects of NK1 Antagonists?
Well tolerated. Fatigue, dizziness, diarrhea. Metabolized by CYP3A4 (chemo drugs also metabolized so increases bone marrow suppression)
What Antihistamines (H1) do you need to know?
Dimenhydrinate, Diphenhydramine, Meclizine
What is the MOA for Antihistamines (H1)?
Sedation. H1 may not be the primary mechanism (might be antimuscarinic effects)
What is the therapeutic use of Antihistamines (H1)?
Antiemetic
What are the side effects of Antihistamines (H1)?
Anticholinergic –> confusion, dry mouth, etc. Interaction with antibiotics. Not to be used in pregnancy.
What are the Dopamine (D2) receptor antagonists you need to know?
Droperidol, Metochlopramide, Prochlorperazine, Promethazine, Thiethylperazine
What is the MOA for Dopamine (D2) Receptor Antagonists?
D2 receptors in CTZ (muscarinic?) antagonism. “Reset” GI motility. Sedation.
What are the side effects for Dopamine (D2) Receptor Antagonists?
Sedation.
What are the two Cannabinoids you need to know?
Dronabinol, Nabilone
What is the MOA for Cannabinoids?
Mimics THC at central cannabinoid receptors. May be sedation.
What are side effects of Cannabinoids?
Euphoria, sedation, hallucinations, dry mouth. Increased appetite (good for cancer patients)
What are cannabinoids given with?
Phenothiazines
Why aren’t cannabinoids used much?
There are better agents available now for cancer therapy.
What two corticosteroids do you need to know?
Dexamethasone and Methylprednisolone
What is the MOA for corticosteroids and antiemesis?
Mechanism in emesis is unknown.
What are corticosteroids used with?
5HT3 antagonists
