NAPLEX QBANK Pharmacology and Mechanism of Action 4

Question 1

Which mechanism explains the antiemetic action of ondansetron?

Accepted Answer

5-HT3 serotonin receptor antagonism

Answer

Dopamine D2 receptor agonism

Answer

Histamine H1 receptor agonism

Answer

Muscarinic M1 receptor agonism

Question 2

Heparin produces anticoagulation primarily by:

Accepted Answer

Enhancing antithrombin III activity

Answer

Inhibiting vitamin K epoxide reductase

Answer

Directly inhibiting thrombin without a cofactor

Answer

Blocking platelet GP IIb/IIIa

Question 3

Which mechanism describes the action of allopurinol in gout?

Accepted Answer

Inhibition of xanthine oxidase reducing uric acid production

Answer

Increasing renal uric acid excretion

Answer

Inhibiting leukocyte migration

Answer

Inhibiting cyclooxygenase

Question 4

Nondihydropyridine calcium channel blockers (e.g., diltiazem) differ from dihydropyridines by:

Accepted Answer

Greater effect on cardiac conduction and rate

Answer

Greater peripheral vasodilation only

Answer

Selective venodilation

Answer

No effect on the AV node

Question 5

The mechanism of action of bisphosphonates (e.g., alendronate) is:

Accepted Answer

Inhibition of osteoclast-mediated bone resorption

Answer

Stimulation of osteoblast proliferation

Answer

Increased intestinal calcium absorption

Answer

RANKL receptor blockade

Question 6

Which mechanism underlies the action of sulfamethoxazole/trimethoprim?

Accepted Answer

Sequential inhibition of folate synthesis pathway

Answer

Inhibition of bacterial DNA gyrase

Answer

Disruption of the cell membrane

Answer

Inhibition of the 30S ribosome

Question 7

Beta-blockers reduce heart rate and contractility by:

Accepted Answer

Antagonizing beta-1 adrenergic receptors

Answer

Blocking L-type calcium channels

Answer

Agonizing muscarinic receptors

Answer

Inhibiting Na+/K+ ATPase