Medical Pharmacology: Gastrointestinal Pharmacology Practice Questions
Choose the correct answer for each question.
5-HT3 receptor blockers are the most effective agents for which one(s) of the following?
Treating postoperative nausea and vomiting in both children and adults.
Treating chemotherapy-induced nausea and vomiting.
Both
Neither
This 5-HT3 antagonist is considered an "second-generation" agent with clear superiority over earlier agents.
Ondansetron (Zofran)
Palonosetron (Aloxi)
Granisetron (Sancuso; Sustol)
Tropisetron (Navoban)
This is a prototypical agent in the group of 5-HT3 receptor antagonists:
Dolasetron
Ondansetron
Granisetron
5-HT3 receptors are localized in which one(s) of this/these locations involved in emesis?
Vagal afferents
Solitary tract nucleus (STN)
Area postrema
A & B
B & C
A & C
A, B & C
Concerning absorption and metabolism of 5-HT3 antagonists:
These agents are typically well absorbed by the G.I. tract and exhibit a rapid onset of pharmacological affect.
Ondansetron is both metabolized by phase I (cytochrome P450 drug metabolizing system) in the liver and subsequently by phase II glucuronidation or sulfation conjugation reactions.
Both
Neither
Patients exhibiting hepatic dysfunction and who are prescribed ondansetron:
These patients may exhibit a decreased rate of drug plasma clearance.
These patients may require dosage adjustment in view of their hepatic dysfunction.
Both
Neither
This drug is considered a "prodrug" converted by plasma carbonyl reductase to the active form
Granisetron
Dolasetron
Ondansetron
The second-generation agent, palonosetron:
Metabolized mainly by the cytochrome P450 isoform CYP2D6.
Both metabolized in and change species are excreted in the urine (in about equal proportions)
Both
Neither
Antiemetics effects of 5-HT3 receptor blockers dissipate rapidly as the drug is eliminated from the circulation.
True
False
5-HT3 receptor antagonists are most usually administered once a day.
