[4] Chapter 3 Pharmacokinetics

Question 1

Effects of the biologic system on drugs

Answer 1

Pharmacokinetics

Question 2

Dose concentration relationship that deals with the processes of absorption, distribution, and elimination of drugs

Answer 2

Pharmacokinetics

Question 3

Amount of drug reaching the plasma

Answer 3

Drug concentration

Question 4

True or False: Drugs need to be separated so free drug is absorbed and distributed

Answer 4

TRUE

Question 5

True or False: Tissue concentration is not proportional to plasma drug concentration

Answer 5

FALSE

Question 6

The measure of the ability of the body to eliminate the drug, most important parameter in designing dosage regimen

Answer 6

Clearance

Question 7

Compliance of patient is important, variation in bioavailability are usually due to variation in metabolism

Answer 7

Absorption

Question 8

Process of delivery to interstitial and intracellular fluids

Answer 8

Distribution

Question 9

The measure of the apparent space in the body available to contain the drug.

Answer 9

Volume of Distribution

Question 10

It describes the predictable relationship between plasma drug concentration and concentration at the receptor site where a given drug produces its therapeutic effect.

Answer 10

Kinetic Homogeneity

Question 11

Most appropriate time to measure drug concentration

Answer 11

Absorption is complete

Question 12

2 hours after the dose, acidic drugs bind to

Answer 12

Albumin

Question 13

Basic drugs bind to

Answer 13

Alpha 1 acid glycoprotein

Question 14

True or False: The more highly protein bound drug will displace, the less protein bound drug

Answer 14

TRUE

Question 15

Unique for a particular drug in a particular patient

Answer 15

Effective drug concentration

Question 16

Two important parameters for effective drug concentration

Answer 16

Volume of Distribution, Clearance

Question 17

Volume of distribution formula

Answer 17

Vd = (amt of drug in body)/ (plasma drug conc)

Question 18

Unit for volume of distribution

Answer 18

Liters or Vd/kg

Question 19

An increase in plasma drug concentration would result to

Answer 19

a decrease in volume of distribution

Question 20

Drug binding to blood and plasma protein

Answer 20

Low distribution

Question 21

Drug bound to peripheral receptors

Answer 21

High distribution

Question 22

Clearance formula

Answer 22

CL=rate of elimination/plasma concentration

Question 23

Unit for clearance

Answer 23

ml/min, L/hr, CL/body wt.

Question 24

Clearance depends on:

Answer 24

Drug, blood flow, condition of the organs of elimination

Question 25

True or False: In most drugs, clearance varies over the concentration range

Answer 25

FALSE

Question 26

Formula for Rate of Elimination

Answer 26

CL * Plasma drug concentration

Question 27

Rate of drug administration is equal to rate of elimination

Answer 27

Steady state concentration

Question 28

Time it takes for concentration of a drug to fall to 50% of an earlier measurement.

Answer 28

Half-life (t1/2)

Question 29

Unit for half life

Answer 29

hrs

Question 30

Half life formula

Answer 30

t1/2 = (0.693 x Vd) / CL

Question 31

True or False: Half life is dependent of volume distribution

Answer 31

TRUE

Question 32

Bioavailability formula

Answer 32

F = (amount of drug in the plasma/dose of drug administered)

Question 33

It is defined as the fraction of unchanged drug reaching the systemic circulation following administration by any route

Answer 33

Bioavailability

Question 34

Fraction of the administered dose of the drug that reaches the systemic circulation

Answer 34

Bioavailability

Question 35

Route with 100% bioavailability and has the most rapid onset, potentially immediate effects although it has increased risk of adverse effects. F=1

Answer 35

Intravenous

Question 36

Route with 75-100% bioavailability with large volumes often feasible; may be painful, appropriate for self administration and has slow sustained from repository preparations. 0.75< F < 1

Answer 36

Intramuscular

Question 37

Route with 75-100% bioavailability with smaller volumes than IM; may be painful. 0.75 < F < 1

Answer 37

Subcutaneous

Question 38

Route with 5 to less than 100 % bioavailability and most convenient but first pass effect may be important, requires patient compliance. 0.05 < F < 1

Answer 38

Oral

Question 39

Route with 30 to less than 100% bioavailability and less first-pass effect than oral

Answer 39

Rectal

Question 40

Route with 5 to less than 100% bioavailability and often very rapid onset

Answer 40

Inhalation

Question 41

Route with 80-100% bioavailability and usually very slow absorption; used for lack of first-pass effect; prolonged duration of action

Answer 41

Transdermal

Question 42

Directly related to concentration

Answer 42

Immediate effect

Question 43

Due to distributional delay

Answer 43

Delayed effect

Question 44

Constant infusion that uses intermittent dosing only

Answer 44

Cumulative effect

Question 45

When desired therapeutic effects are produced.

Answer 45

Target concentration

Question 46

Plan for drug administration over a period of time. Achievement of therapeutic levels of the drug in the body without exceeding the minimum toxic concentration.

Answer 46

Dosage Regimens

Question 47

Dosing rate formula

Answer 47

Dosing rate = (CL x desired plasma conc) / bioavailability

Question 48

Dose needed to maintain a steady state of concentration; to maintain plasma concentration over periods of time

Answer 48

Maintenance dose

Question 49

Loading dose formula

Answer 49

Loading dose = (Vd x desired concentration) / Bioavailability

Question 50

Administered for drugs with long half-lives and longer time to reach a steady state; to achieve target plasma level rapidly

Answer 50

Loading dose

Question 51

Given to promptly raise the concentration of the drug to the target concentration.

Answer 51

Loading Dose

Question 52

True or False: If loading dose is large, dose should be given rapidly to prevent toxicity

Answer 52

FALSE

Question 53

Most important parameter in designing dosage regimen

Answer 53

Clearance

Question 54

Fraction or percentage of the drug removed from the perfusing blood during passage through the organ

Answer 54

Extraction Ratio

Question 55

Drugs are eliminated unchanged or as metabolites

Answer 55

Excretion

Question 56

Important organs for excretion

Answer 56

Kidneys, Liver, GIT, Breast, Lungs

Question 57

Safe "opening" between the MEC and the MTC of the drug.

Answer 57

Therapeutic Window

Question 58

It determines the desired trough levels of a drug given intermittently.

Answer 58

Minimum effective concentration

Question 59

Determines the peak

Answer 59

Maximum toxic concentration

Question 60

It determines the permissible peak plasma concentration

Answer 60

Minimum Toxic concentration / Maximum Therapeutic Concentration