EXAM 2 Reading (N.Ch6)

Question 1

The plasma half-life of a drug is inversely proportional to its

Answer 1

Rate of clearance

Question 2

When you administer a bolus dose of a drug intravenously, which tissue would have an increase in the tissue concentration of the drug first?

Answer 2

Liver

Question 3

The vessel-rich group,

Answer 3

which is comprised of the highly-perfused organs such as the brain, heart, liver, kidneys, lungs, and endocrine organs, receives 75% of the cardiac output.

Question 4

They exhibit the most rapid equilibration of the drug with the blood (which group) ?.

Answer 4

The vessel-rich group

Question 5

After distribution to the vessel-group, The drug then

Answer 5

redistributes to other, less-perfused tissues such as muscle, adipose tissue, and bone.

Question 6

What is the most prevalent protein in the bloodstream?

Answer 6

Albumin

Question 7

Which of the following plasma proteins binds preferably to acidic drugs?

Answer 7

Albumin is capable of binding drugs that are alkaline or neutral, but binds preferably to acidic drugs.

Question 8

2 proteins that bind preferably to basic drugs.

Answer 8

Alpha-1 acid glycoprotein and Beta-globulin

Question 9

Proteins that binds to corticosteroids.

Answer 9

Transcortin

Question 10

Approximately what percent of the cardiac output goes to the adipose tissue group?

Answer 10

6%

Question 11

The vessel-rich group receives ___%of the cardiac output.

Answer 11

75%

Question 12

The muscle group receives about____% of the cardiac output

Answer 12

19%

Question 13

The adipose group receives ____% of the cardiac output,

Answer 13

6%

Question 14

Vessel-poor group receives a

Answer 14

% negligible proportion

Question 15

Which of the following agents exemplifies zero-order kinetics?

Answer 15

Alcohol (ethanol)

Question 16

Zero-order kinetics refers to metabolism in which

Answer 16

the amount of the drug eliminated over time is constant.

Question 17

The clearance of a drug is inversely proportional to

Answer 17

its half-life

Question 18

The clearance of a drug is defined as the C.

Answer 18

volume of plasma that is cleared of a drug per unit of time and is dependent upon the body’s ability to metabolize and eliminate the drug.

Question 19

The formula for clearance is

Answer 19

Clearance = Q X E (where Q is blood flow and E is the extraction ratio).

Question 20

Clearance is _____-(definition) - What does it mean?

Answer 20

directly proportional to the dose administered and inversely related to the half-life of the drug. Meaning, as the half-life of the drug increases, the volume that is cleared per unit of time decreases.

Question 21

How does hypoalbuminemia affect the action of a highly protein-bound drug like warfarin?

Answer 21

Its effect is intensified

Question 22

% of warfarin is protein-bound

Answer 22

About 98

Question 23

As the plasma protein level decreases, there is

Answer 23

less of the protein available for the drug to bind with, and more of the free form of the drug is available to exert its pharmacologic action.

Question 24

Hypoalbuminemia and highly protein bound drugs?

Answer 24

hypoalbuminemia intensifies the action of highly protein-bound drugs.

Question 25

Which of the following statements are correct? (select two) | Plasma half life and zero-order kinetic

Answer 25

The plasma half-life of a drug is inversely proportional to its rate of clearance A drug with zero-order kinetics exhibits a constant rate of elimination

Question 26

Enzyme induction

Answer 26

reduces the plasma half-life of agents that are metabolized by that particular metabolic pathway.

Question 27

According to the Fick equation, the most important factor in determining the rate of diffusion of a drug across a membrane is the

Answer 27

concentration gradient of the drug.

Question 28

Membrane thickness is an important factor in the

Answer 28

rate of diffusion

Question 29

Molecular weight, which affects the

Answer 29

diffusion coefficient (p)

Question 30

Which of the following drugs will be more non-ionized than ionized at physiologic pH? (select two)

Answer 30

An acid with a pKa of 9.5 | A base with a pKa of 4.2

Question 31

For a WEAK ACID explain ph vs pka

Answer 31

pH < Pka --> Nonionized | pH > Pka --> Ionized

Question 32

For a WEAK BASE explain ph vs pka

Answer 32

pH < Pka --> IOnized | pH > Pka --> NOn-Ionized

Question 33

Which pharmacokinetic model best illustrates how lipid-soluble drugs are distributed?

Answer 33

Two-compartment model

Question 34

For many drugs, a single-compartment model, which represents In

Answer 34

the distribution of the drug throughout the entire body sufficiently explains the pharmacokinetics of the drug.

Question 35

For lipid-soluble drugs, however, what better illustrates how the drug is distributed?

Answer 35

two-compartment model better illustrates how the drug is distributed.

Question 36

The peripheral compartment consists of the

Answer 36

muscles, adipose tissue, and bone

Question 37

The two-compartment model, there is a central compartment, which consists of the

Answer 37

intravascular fluid and highly perfused tissues such as the heart, lungs, brain, kidneys, and live

Question 38

Two-compartment membrane include the

Answer 38

Central and peripheral compartments

Question 39

Immediately after administration of a bolus dose of a particular drug that undergoes first-order kinetics, you measure the plasma concentration, and it is 100 mcg/mL. The drug has an elimination half-life of 5 minutes. What would you expect the plasma concentration to be 15 minutes after the initial administration?

Answer 39

The elimination half-life of the drug is five minutes. The passing of 15 minutes would constitute three half-lives. With each half-life, the plasma concentration of the drug should drop by half. So, after the first five minutes, it would be 50 mcg/mL. After the second five minutes, it should be 25 mcg/mL. After the third five minutes, it should be 12.5 mcg/mL.

Question 40

Which form of a drug is responsible for reaching the site of action?

Answer 40

Non-Ionized

Question 41

In solution, the non-ionized form of a drug is considered to confer pharmacologic activity, because it is in then

Answer 41

non-ionized form that the drug is able to pass through lipid-soluble biologic membranes to reach its point of actio

Question 42

Which term refers to the amount of the drug that is able to reach its target receptor after it is introduced into the circulatory system?

Answer 42

Bioavailability

Question 43

A drug is being administered by continuous infusion, and its plasma concentration is now constant. The drug is said to be in

Answer 43

a steady state

Question 44

Steady state refers to a .

Answer 44

stable plasma concentration of a drug.

Question 45

With a single dose of a drug, the plasma concentration

Answer 45

increases as it is absorbed, reaches a peak plasma concentration, and then decreases as it is eliminated.With the chronic administration of a drug or a continuous infusion, however, the supply of the drug is continually renewed

Question 46

Once the rate at which it becomes bioavailable equals the rate at which it is eliminated, the plasma concentration becomes

Answer 46

stable, and the drug is said to be at a steady state.

Question 47

Presystemic elimination would be most likely to occur in a drug administered

Answer 47

Orally

Question 48

Drugs administered orally may undergo_____What does it mean?

Answer 48

presystemic elimination. That is, they may be eliminated before they are able to reach the systemic circulation

Question 49

What is the first-pass hepatic elimination.

Answer 49

The stomach acids may hydrolyze the drug, gastric enzymes can deactivate it, or it can be metabolized in the liver as it passes through the portal circulation before it reaches the systemic circulation, a process known as

Question 50

The clearance of a drug is dependent upon (2)

Answer 50

blood flow and the Extraction ratio

Question 51

There are also separate concepts of hepatic clearance and renal clearance that become important

Answer 51

when one or both organs has an alteration in either blood flow or the extraction ratio.

Question 52

In pharmacokinetics, steady-state refers to a situation in which

Answer 52

the concentration of a drug in the tissues does not change from moment-to-moment

Question 53

Steady-state refers to a state in which all of the tissues in the body have

Answer 53

had time to reach equilibrium.

Question 54

Which route of administration requires a significantly higher dosage in most drugs to achieve a therapeutic plasma concentration?

Answer 54

Oral

Question 55

Because of extensive first-pass metabolism, the oral dose of most drugs must be significantly

Answer 55

higher to generate therapeutic plasma concentrations.

Question 56

The administration of lidocaine to a parturient can result in an increased concentration of the drug in the fetus. This concept that describes why this occurs is

Answer 56

ion trapping

Question 57

Explain ion trapping?

Answer 57

When the lipid-soluble portion of a basic drug like lidocaine crosses the placenta and enters the acidic environment of the fetus, the drug becomes more ionized and unable to cross back through the placenta. As a result, a higher concentration of the drug exists in the fetus than in the mother. This concept is known as ion trapping.

Question 58

The diffusion of a drug across a membrane from an area of higher concentration to an area of lower concentration without the expenditure of energy is

Answer 58

Passive Transport

Question 59

Which of the following measurements predicts the time it takes for 50% of a drug to be eliminated from the central compartment when a continuous infusion is discontinued?

Answer 59

Context-sensitive half-time

Question 60

The context-sensitive half-time predicts the time it takes for

Answer 60

50% of a drug to be eliminated from the central compartment when a continuous infusion is discontinued.

Question 61

The volume of distribution describes the

Answer 61

virtual volume into which the drug is distributed.

Question 62

The steady-state plasma concentration corresponds to the

Answer 62

steady concentration at the site of action and is determined by a concentration-response curve

Question 63

It should be noted that context sensitive half-times are computer models that only

Answer 63

predict the time for 50% of the drug in the central compartment to be eliminated. It does not predict the time for recovery from the drug.

Question 64

Which route of administration will produce a lower bioavailability of most drugs due to rapid metabolism in the liver via the first-pass effect?

Answer 64

Oral

Question 65

Approximately how much of a drug will be remaining in the bloodstream after four elimination half-lives have passed for a drug that undergoes first-order kinetics?

Answer 65

5%

Question 66

Which drug administration route would have the highest bioavailability?

Answer 66

IV

Question 67

The intravenous route, by definition has __% bioavailability, has a

Answer 67

100% bioavailability because the entire dose of drug administered is available within the circulatory system immediately.

Question 68

Intramuscular and subcutaneous administration both range between

Answer 68

75 and 100% bioavailability.

Question 69

Routes such as oral, topical, and inhalation can vary widely depending on the chemical characteristics of the particular drug and how they affect its ability to be

Answer 69

absorbed into the bloodstream.

Question 70

Hepatic enzyme induction will result in a reduction in the ____ of a drug.

Answer 70

Half life.

Question 71

If liver enzymes are exposed to particular compounds or drugs over a period of time, they will

Answer 71

increase their activity, resulting in an increased ability to metabolize the drugs. This is referred to as hepatic enzyme induction, and it can result in a reduced half-life of a drug

Question 72

The plasma half-life of a drug is directly proportional to its

Answer 72

Volume of distribution

Question 73

Which is the single most important enzyme, accounting for 40-45 percent of all mediated drug metabolism?

Answer 73

CYP3A4