Question 1

Which of the following statements best describes the primary purpose of drug metabolism in the human body?

Accepted Answer

To enhance the removal of drug molecules by increasing their water solubility.

Question 2

A drug molecule contains a methyl ether group. Which metabolic transformation is most likely to occur at this site, and what is the required condition for this reaction?

Accepted Answer

Oxidative O-dealkylation; requires a hydrogen atom on the carbon adjacent to the ether oxygen.

Question 3

Which enzyme family is responsible for catalyzing the majority of oxidative Phase I metabolic reactions in drug metabolism?

Accepted Answer

Cytochrome P450 (CYP450)

Question 4

A patient is prescribed a drug that is primarily metabolized by CYP2D6. Which of the following scenarios could lead to increased plasma levels of the drug?

Accepted Answer

The patient is a poor CYP2D6 metabolizer due to genetic polymorphism.

Question 5

Which of the following functional groups is most likely to undergo glucuronide conjugation during Phase II metabolism?

Accepted Answer

A phenolic hydroxyl group

Question 6

A drug molecule contains a nitro group. Which sequence of metabolic transformations could convert this group to a primary amine?

Accepted Answer

Reduction to nitroso, then to hydroxylamine, then to primary amine

Question 7

Which of the following best explains why some drugs do not require metabolic transformation before excretion?

Accepted Answer

They possess sufficient water solubility due to ionizable or hydrogen-bonding functional groups.

Question 8

Which of the following is a key requirement for CYP450-catalyzed oxidation of a carbon atom in a drug molecule?

Accepted Answer

The carbon must have at least one hydrogen atom attached.

Question 9

A patient overdoses on acetaminophen. Which Phase II metabolic pathway is most critical for detoxifying the reactive intermediate formed during acetaminophen metabolism?

Accepted Answer

Glutathione conjugation

Question 10

Which of the following statements about Phase II conjugation reactions is CORRECT?

Accepted Answer

All Phase II conjugations require an initial activation step except glutathione conjugation.

Question 11

A drug contains a primary amine adjacent to a carbon with a hydrogen atom. Which Phase I metabolic transformation is most likely to occur?

Accepted Answer

Oxidative deamination

Question 12

Which of the following best describes the difference between oxidative deamination and N-dealkylation?

Accepted Answer

Oxidative deamination removes an amine group, while N-dealkylation removes an alkyl group from nitrogen.

Question 13

Which of the following is a likely outcome if a drug molecule contains a sterically hindered functional group?

Accepted Answer

It will be less likely to undergo metabolic transformation.

Question 14

Which of the following is TRUE regarding the metabolism of prodrugs?

Accepted Answer

Prodrugs are inactive or weakly active compounds that require metabolic activation, often by Phase I oxidation or hydrolysis.

Question 15

Which of the following metabolic transformations is most likely to occur at the para position of an unsubstituted phenyl ring?

Accepted Answer

Aromatic hydroxylation

Question 16

A drug molecule contains a carboxylic acid functional group. Which Phase II conjugation pathway is most likely to occur?

Accepted Answer

Amino acid conjugation

Question 17

Which of the following best explains why tertiary hydroxyl groups are less likely to undergo glucuronide conjugation?

Accepted Answer

They are sterically hindered, making them less accessible to transferase enzymes.

Question 18

Which of the following is a possible consequence of co-administering a strong CYP3A4 inhibitor with a drug metabolized by CYP3A4?

Accepted Answer

Increased plasma concentration of the drug due to decreased metabolism.

Question 19

Which of the following is a correct statement about the role of glutathione in drug metabolism?

Accepted Answer

Glutathione conjugation detoxifies highly reactive electrophilic intermediates and cannot be reversed by deconjugating enzymes.

Question 20

Which of the following best describes the effect of age on drug metabolism?

Accepted Answer

Drug metabolism generally decreases with age, requiring dose adjustments in elderly patients.

Drug Metabolism: Principles, Mechanisms, and Pathways

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