FREE NAPLEX QBANK Pharmacology and Drug Mechanisms Questions and Answers

Question 1

A patient with heterozygous familial hypercholesterolemia is prescribed alirocumab. What is the primary mechanism of action of this medication?

Accepted Answer

It binds to proprotein convertase subtilisin/kexin type 9 (PCSK9), preventing its interaction with LDL receptors.

Answer

It directly inhibits HMG-CoA reductase in the liver, reducing cholesterol synthesis.

Answer

It blocks the intestinal absorption of cholesterol by inhibiting the Niemann-Pick C1-Like 1 (NPC1L1) protein.

Answer

It activates peroxisome proliferator-activated receptor alpha (PPAR-α), increasing lipoprotein lipase activity.

Question 2

A 58-year-old male with newly diagnosed type 2 diabetes mellitus is started on metformin. Which of the following best describes the primary mechanism by which metformin exerts its antihyperglycemic effect?

Accepted Answer

Activation of AMP-activated protein kinase (AMPK), leading to decreased hepatic gluconeogenesis.

Answer

It acts as a secretagogue, stimulating insulin release from pancreatic beta cells.

Answer

It inhibits the dipeptidyl peptidase-4 (DPP-4) enzyme, increasing incretin levels.

Answer

It acts as a sodium-glucose cotransporter-2 (SGLT2) inhibitor in the proximal renal tubules.

Question 3

A patient who was recently started on lisinopril for hypertension develops a persistent, non-productive cough. This adverse effect is primarily attributed to the accumulation of which substance in the respiratory tract?

Accepted Answer

Bradykinin

Answer

Angiotensin II

Answer

Aldosterone

Answer

Histamine

Question 4

A patient is brought to the emergency department with respiratory depression and miosis. An opioid overdose is suspected. Administration of naloxone rapidly reverses these symptoms. By what mechanism does naloxone work?

Accepted Answer

It acts as a competitive antagonist at mu, kappa, and delta opioid receptors.

Answer

It acts as a partial agonist at the mu-opioid receptor, displacing the full agonist.

Answer

It increases the metabolic clearance of opioids by inducing hepatic enzymes.

Answer

It stimulates the release of endogenous endorphins to counteract the opioid effect.

Question 5

Which of the following statements most accurately describes the pharmacological mechanism of selective serotonin reuptake inhibitors (SSRIs) like sertraline?

Accepted Answer

They selectively block the presynaptic serotonin transporter (SERT), increasing serotonin concentration in the synaptic cleft.

Answer

They inhibit both serotonin and norepinephrine reuptake transporters with high affinity.

Answer

They block postsynaptic serotonin 5-HT2A receptors while also inhibiting serotonin reuptake.

Answer

They inhibit the enzyme monoamine oxidase, preventing the breakdown of serotonin.

Question 6

The anxiolytic and sedative effects of diazepam are produced by which of the following molecular actions on the GABA-A receptor?

Accepted Answer

Potentiating the effects of GABA by increasing the frequency of chloride channel opening.

Answer

Directly activating the GABA-A receptor in the absence of GABA.

Answer

Increasing the duration of chloride channel opening when GABA is bound.

Answer

Blocking the reuptake of GABA from the synaptic cleft.