NAPLEX QBANK Pharmacology and Drug Mechanisms 2

Question 1

Which mechanism explains the antiplatelet effect of clopidogrel?

Accepted Answer

Irreversible P2Y12 ADP receptor blockade

Answer

Clopidogrel's active metabolite irreversibly inhibits the platelet P2Y12 ADP receptor.

Question 2

A patient on warfarin starts amiodarone; what is the expected interaction?

Accepted Answer

Increased INR from CYP2C9/CYP3A4 inhibition

Answer

Amiodarone inhibits CYP2C9 and CYP3A4, raising warfarin levels and INR.

Question 3

Which diuretic acts on the Na-K-2Cl cotransporter in the thick ascending limb?

Accepted Answer

Furosemide

Answer

Loop diuretics like furosemide inhibit the Na-K-2Cl cotransporter.

Question 4

The mechanism of metformin's glucose-lowering effect primarily involves:

Accepted Answer

AMPK activation and decreased hepatic gluconeogenesis

Answer

Metformin activates AMPK and reduces hepatic glucose production.

Question 5

Which receptor does ondansetron antagonize to prevent nausea?

Accepted Answer

5-HT3 serotonin receptor

Answer

Ondansetron blocks 5-HT3 receptors centrally and in the GI tract.

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