Pharmacokinetics (M1)

Question 1

What determines the plasma concentration for pharmacokinetics?

Answer 1

1. absorption
2. distribution
3. elimination

Question 2

What is the movement of the drug into the bloodstream?

Answer 2

absorption

Question 3

What refers to the process of a drug leaving the bloodstream and going into the organs and tissues?

Answer 3

distribution

Question 4

What are the processes that elimination of a drug relies on (and where do each primarily occur)?

Answer 4

1. biotransformation, metabolism (liver)

2. excretion (kidneys)

Question 5

What are the three classes of membrane lipids?

Answer 5

1. phospholipids
2. cholesterol
3. glycolipids

Question 6

What is found in the bilayer and helps to hold the membrane together while making it less deformable and less permeable?

Answer 6

cholesterol

Question 7

What form of drugs (ionized or nonionized) is sufficiently soluble in membrane lipids to cross membranes?

Answer 7

nonionized

Question 8

What weak acids, which form is nonionized?

Answer 8

protonated

Question 9

What weak bases, which form is nonionized?

Answer 9

nonprotonated

Question 10

What is the pH at which there are equal amounts of the protonated and nonprotonated form?

Answer 10

pKa

Question 11

What is the Henderson-Hasselbalch equation?

Answer 11

pKa = pH + log ((protonated)/(unprotonated))

Question 12

What is the Henderson-Hasselbalch equation for a weak acid?

Answer 12

pKa = pH + log([nonionized acid]/[ionized acid])

Question 13

What is the Henderson-Hasselbalch equation for a weak base?

Answer 13

pKa = pH + log([ionized base]/[nonionized base])

Question 14

What is the faction of unchanged administered drug that reaches the systemic circulation following administration?

Answer 14

bioavailability

Question 15

What is the bioavailability in regards to graphs?

Answer 15

area under the blood concentration-time curve

Question 16

What does a P-glycoprotein affect? 1. What does it contain to make this happen? 2

Answer 16

1. extent of absorption

2. Multi-drug resistance-assoicated protein (MRP) transporters

Question 17

What is the extraction ratio equation?

Answer 17

ER = CL(liver)/Q
CL is clearance
Q is hepatic blood flow

Question 18

What is the bioavailability equation?

Answer 18

F = f*(1-ER) = AUC(oral)/AUC(IV)

Question 19

What type of kinetics do most drugs follow in terms of absorption?

Answer 19

first order kinetics

Question 20

What type of kinetics do IV drugs follow in terms of absorption?

Answer 20

zero order kinetics

Question 21

Through what does the distribution of drugs mainly get done?

Answer 21

1. circulatory

2. lymphatic

Question 22

What is the volume of distribution equation?

Answer 22

Vd = (amount of drug in body)/(conc. in plasma)

Question 23

What are the factors affecting distribution of a drug?

Answer 23

1. organ blood flow
2. plasma protein binding
3. molecular size
4. lipid solubility

Question 24

What is the role of biotransformation of drugs?

Answer 24

1. inactive and detoxify
2. more water soluble to excrete
3. could activate (Pro-drugs)

Question 25

What methods of administration of drugs undergo less first-pass metabolism?

Answer 25

1. sublingual

2. rectal

Question 26

What is phase I of biotransformation reactions?

Answer 26

oxidative, hydrolytic, reductive reactions to convert to a polar metabolite

Question 27

What is the major family of enzymes responsible for phase I biotransformation reactions?

Answer 27

Microsomal cytochrome P450 (CYP) monooxygenase system

Question 28

What are the reactions that take place in phase II biotransformation? 1. What are required to perform this? 2. What is the end result? 3

Answer 28

1. conjugation reactions
2. endogenous substance and conjugation enzymes (transferases)
3. form water-soluble metabolites for easier excretion

Question 29

What are the three types of phase II biotransformation reactions?

Answer 29

1. glucuronide formation
2. acetylation
3. sulfation

Question 30

What are the three types of variations that most often affect pharmacogenomics?

Answer 30

1. acetyltransferase activity
2. CYP2D6 and CYP2C19 activity (most)
3. drug metabolism enzymes

Question 31

What is the syndrome in infants where they don’t metabolize drugs well because phase I results in toxic metabolite and phase II is not ready for them?

Answer 31

gray baby syndrome

Question 32

What does the rate of drug elimination through the kidneys depend on?

Answer 32

balance of drug filtration, secretion, and reabsorption rates

Question 33

Which form of a drug is filtered into the renal tubule and which is not?

Answer 33

free (unbound) drug is filtered and plasma protein-bound drug is not

Question 34

What factors in renal excretion cause the process to happen more rapidly?

Answer 34

1. enhancing blood flow
2. increasing glomerular filtration rate
3. decreasing protein binding

Question 35

What makes some drugs secrete from the liver into the bile, to later be excreted through the GI tract?

Answer 35

ATP binding cassette (ABC) transporters, most commonly MDR family

Question 36

What type of clearance do most drugs follow? 1. How is this shown on a graph? 2

Answer 36

1. first-order elimination (elimination directly proportional to conc)
2. area under the curve of the time-concentration profile (AUC)

Question 37

When do drugs follow zero-order kinetics (rate of elimination constant) in terms of clearance?

Answer 37

when clearance mechanisms are saturated

Question 38

In what kind of urine are weak acids excreted faster?

Answer 38

alkaline urine

Question 39

In what kind of urine are weak bases excreted faster?

Answer 39

acidic urine

Question 40

What is the equation for the half-life of a drug?

Answer 40

t(1/2) = (0.693*Vd)/CL

Question 41

What is the maintenance dose equation?

Answer 41

maintenance dose = (dosing rate)*(dosing interval)

Question 42

What is used to promptly raise the concentration of a drug in the plasma to target concentration?

Answer 42

loading dose