PTCB Pharmacology #1 3

Question 1

Which enzyme does warfarin inhibit to produce its anticoagulant effect?

Accepted Answer

Vitamin K epoxide reductase

Answer

Warfarin inhibits vitamin K epoxide reductase, preventing the recycling of vitamin K. This depletes vitamin K-dependent clotting factors (II, VII, IX, X) and proteins C and S.

Question 2

Statins reduce LDL cholesterol primarily by:

Accepted Answer

Inhibiting HMG-CoA reductase in the liver

Answer

Statins competitively inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis, reducing intracellular cholesterol and upregulating LDL receptors on hepatocytes.

Question 3

A drug with a narrow therapeutic index (NTI) is best described as:

Accepted Answer

A drug where there is little difference between the effective and toxic dose

Answer

Narrow therapeutic index drugs (e.g., warfarin, digoxin, lithium, phenytoin) have a small window between therapeutic and toxic concentrations, requiring close monitoring and dose adjustments.

Question 4

Omeprazole (Prilosec) is an example of which type of drug?

Accepted Answer

Proton pump inhibitor

Answer

Omeprazole is a PPI (proton pump inhibitor) that irreversibly inhibits the H+/K+ ATPase. H2 blockers (ranitidine, famotidine) reversibly block histamine H2 receptors on parietal cells.

Question 5

Which of the following neurotransmitters is primarily affected by SSRI antidepressants?

Accepted Answer

Serotonin

Answer

SSRIs (selective serotonin reuptake inhibitors) block the serotonin transporter (SERT), increasing synaptic serotonin levels. SNRIs affect both serotonin and norepinephrine.

Pharmacy Practice Test

Pharmacy Practice Test

PTCB Pharmacology #1 3