Lecture 4

Question 1

What are endosomes?

Answer 1

Membrane-bound structures inside the cell

Formed when a cell engulfs substances via endocytosis.

Question 2

What is endocytosis?

Answer 2

Brings material into the cell

Involves the engulfing of substances by the cell.

Question 3

What is exocytosis?

Answer 3

Moves material out of the cell

Contents of endosomes may merge back with the membrane via this process.

Question 4

Define clearance (CL) in pharmacokinetics.

Answer 4

Volume of blood cleared of a drug per unit time.

Question 5

What is the rate of elimination in pharmacokinetics?

Answer 5

Actual amount of drug removed per unit time.

Question 6

What characterizes zero-order kinetics?

Answer 6

Rate of elimination is constant regardless of drug concentration.

Question 7

What is a loading dose?

Answer 7

Quickly reaches therapeutic concentration without waiting for multiple half-lives.

Question 8

What is steady state in pharmacokinetics?

Answer 8

Maintains a constant drug concentration by balancing administration and elimination.

Question 9

What does therapeutic drug monitoring (TDM) measure?

Answer 9

Peak and trough levels

Accounts for genetic variability in drug metabolism.

Question 10

How do lipophilic drugs distribute in the body?

Answer 10

Distribute into fat.

Question 11

How do hydrophilic drugs distribute in the body?

Answer 11

Remain in plasma.

Question 12

What is creatinine clearance used for?

Answer 12

Estimates renal function.

Question 13

What does lower creatinine clearance indicate?

Answer 13

Slower drug elimination.

Question 14

What are the two main phases of drug biotransformation?

Answer 14

• Phase I Reactions
• Phase II Reactions

Question 15

What occurs during Phase I reactions?

Answer 15

Oxidation, reduction, hydrolysis; makes drugs more polar and water-soluble.

Question 16

What is the role of Cytochrome P450 enzymes?

Answer 16

Mediates Phase I reactions; can activate, inactivate, or partially modify drugs.

Question 17

What occurs during Phase II reactions?

Answer 17

Conjugation reactions—attach large molecules to increase molecular weight and water solubility.

Question 18

Which CYP450 enzyme metabolizes approximately 50% of drugs?

Answer 18

CYP3A4.

Question 19

Which enzyme metabolizes opioids like codeine?

Answer 19

CYP2D6.

Question 20

What do star (*) alleles indicate?

Answer 20

Enzyme variants.

Question 21

What does poor metabolizer status imply?

Answer 21

Slow drug clearance.

Question 22

What does the term ‘inducers’ refer to in drug interactions?

Answer 22

Increase enzyme activity → faster drug metabolism.

Question 23

What effect do inhibitors have on enzyme activity?

Answer 23

Decrease enzyme activity → slower metabolism.

Question 24

What is the effect of acetaminophen overdose?

Answer 24

Produces toxic metabolites due to glutathione depletion.

Question 25

What is the antidote for acetaminophen overdose?

Answer 25

N-acetylcysteine.

Question 26

What does pharmacogenomics study?

Answer 26

How genetic differences affect drug metabolism.

Question 27

What is personalized medicine?

Answer 27

Right drug, dose, and time for the right patient.

Question 28

Fill in the blank: Codeine efficacy depends on _______.

Answer 28

CYP2D6 activity.

Question 29

Fill in the blank: Warfarin sensitivity is affected by _______.

Answer 29

CYP2C9 variants.

Question 30

Fill in the blank: Cancer treatments like Herceptin require _______ testing.

Answer 30

HER2.