Ch 84 Antiemetics

Question 1

Drug: Ondansetron (Zofran)

Answer 1

Class: Serotonin 5-HT₃ receptor antagonist
MOA: Blocks 5-HT₃ receptors in the CTZ and GI tract.
Note:
* First-line for chemotherapy-induced nausea and vomiting (CINV)
* may prolong QT interval

Question 2

Drug: Prochlorperazine (Compazine)

Answer 2

Class: Dopamine antagonist (phenothiazine)
MOA: Blocks D2 receptors in the CTZ.
Note: Can cause sedation and extrapyramidal symptoms.
CI: children < 2years

Question 3

Drug: Dronabinol (Marinol)

Answer 3

Class: Cannabinoid antiemetic
MOA: Unknown for emesis; acts on cannabinoid receptors.
Note: Synthetic THC; appetite stimulant; potential for abuse.

Question 4

Drug: Scopolamine (Transderm Scop)

Answer 4

Class: Anticholinergic
MOA: Blocks muscarinic receptors involved in the vomiting reflex.
Note: Used for motion sickness; side effects include dry mouth and drowsiness.

Question 5

Drug: Metoclopramide (Reglan)

Answer 5

Class: Dopamine antagonist; prokinetic agent
MOA: Blocks dopamine and serotonin receptors in the CTZ supressing emesis; increases upper GI motility.
Note: Risk of tardive dyskinesia with long-term use.