GI GI Pharmacology and Medications 3

Question 1

Metoclopramide is a prokinetic agent used in gastroparesis; which receptor does it primarily antagonize to enhance gastric emptying?

Accepted Answer

Dopamine D2 receptor

Answer

Metoclopramide antagonizes dopamine D2 receptors in the GI tract and CNS, enhancing gastric antral contractions and accelerating gastric emptying.

Question 2

Vancomycin administered orally is effective for Clostridioides difficile infection because:

Accepted Answer

It remains in the intestinal lumen without systemic absorption

Answer

Oral vancomycin is not absorbed from the GI tract, achieving high luminal concentrations that kill C. difficile directly in the colon.

Question 3

Azathioprine and 6-mercaptopurine are thiopurine immunosuppressants used in IBD; deficiency of which enzyme leads to toxic drug accumulation?

Accepted Answer

Thiopurine methyltransferase (TPMT)

Answer

TPMT deficiency impairs thiopurine methylation, causing accumulation of cytotoxic thioguanine nucleotides and severe bone marrow suppression.

Question 4

Which agent is the first approved for fecal microbiota transplantation (FMT) by the FDA for recurrent C. difficile infection?

Accepted Answer

Rebyota (fecal microbiota, live-jslm)

Answer

Rebyota (RBX2660) received FDA approval in 2022 as the first approved microbiota-based live biotherapeutic for recurrent C. difficile infection.

Question 5

Non-selective beta-blockers (e.g., propranolol, nadolol) are used in cirrhosis primarily to prevent which complication?

Accepted Answer

First and recurrent variceal hemorrhage

Answer

Non-selective beta-blockers reduce portal pressure by decreasing cardiac output (β1) and causing splanchnic vasoconstriction (β2), preventing variceal bleeding.

Gastrointestinal GI Practice Practice Test

Gastrointestinal GI Practice Practice Test

GI GI Pharmacology and Medications 3