Pharmacology I

Question 1

pharmacokinetics

Answer 1

movement of a drug through the body to the target site and then out of the body 4 step process 1. absorption 2. distribution 3. metabolism 4. clearance

Question 2

Total % body weight that is water

Answer 2

60%

Question 3

Total % body weight water that is extracellular

Answer 3

20%

Question 4

Total % body weight water and ml/kg that is intracellular

Answer 4

40%; 0.4 L/kg

Question 5

Total % body water weight and ml/kg that is interstitial

Answer 5

16%; 0.16 L/kg

Question 6

Total % body weight water that is located in the plasma and ml/kg

Answer 6

4%; 0.04 L/kg

Question 7

Most drugs reach their target site by traveling through the _____ and then transversing out

Answer 7

blood

Question 8

Once in the circulatory system, a drug will distribute into the three body water compartments. List those compartments

Answer 8

Plasma (seperated by the epithelial layer) Interstitial (separated by the endothelial layer) Intracellular

Question 9

Except for target IV drugs the amount of drug reaching the target is never _____

Answer 9

100%

Question 10

Vd

Answer 10

Volume of distribution is the volume of total body water into which a drug will partition Vd= Q (dosage in mg)/Cp (plasma concentration (mg/l)

Question 11

About how many liters of water are in a 75 kg adult

Answer 11

45 L

Question 12

Many drugs bind/do not bind to plasma proteins, retaining them in the plasma and increasing/reducing their Vd

Answer 12

bind; decreasing

Question 13

serum protein that and acidic drug would bind to

Answer 13

albumin ex. warfarin

Question 14

serum protein that and basic drug would bind to

Answer 14

alpah1- acid glycoprotein

Question 15

serum protein that and hydrophobic drug would bind to

Answer 15

lipoproteins

Question 16

serum protein that and steroid hormone would bind to

Answer 16

globulins

Question 17

Rank in order from highest water weight to lowest to highest water weight for brain, adipose tissue, and muscle

Answer 17

1. adipose 2. brain (0.75l/kg) 3. Muscle (0.76 l/kg)

Question 18

total body water content varies based on ______ and ______

Answer 18

age; total body fat content

Question 19

older people tend to have less/more water weight

Answer 19

less

Question 20

children tend to have less/more water weight

Answer 20

more

Question 21

How does increased fat content affect total water weight

Answer 21

less water weight because increased water weight correlates with muscle

Question 22

lipophilic

Answer 22

sometimes the Vd can be greater than the total volume of water in the body ex. propofol

Question 23

Three reasons why Vd can be greater than the total volume of water int he body

Answer 23

1. possible because Vd and Cp are inversely related 2. hydrophobicity 3. weak base drug concentrating in lysosomes due to ph trapping

Question 24

Tissues whose cells have high levels of lysosomes

Answer 24

lungs, liver, muscle, and brain

Question 25

An example of drug class that participates in ph trapping in cellular lysosomes

Answer 25

selective serotonin reuptake inhibitor antidepressants (SSRIs)

Question 26

plasma protein binding drug will **increase/decrease** Vd

Answer 26

decrease

Question 27

tissue binding drug and drugs that participate in ph trapping will **increase/decrease** Vd

Answer 27

increase

Question 28

all drugs that are intended to reach general circulation must at least pass through ______ layer of ________ cells

Answer 28

one; epithelial

Question 29

**hydrophobic/hydrophilic** drugs are absorbed through the lipid bilayers of epithelial and endothelial cells

Answer 29

hydrophobic

Question 30

many drugs are **weak/strong** acids and **weak/strong** bases

Answer 30

weak; weak

Question 31

**protonated/un-protonated** form of a weak acid can be absorbed

Answer 31

protonated because it will be uncharged and therefore will be hydrophobic

Question 32

pka below pH

Answer 32

deprotonated form persists

Question 33

pka above pH

Answer 33

protonated for persists

Question 34

**protonated/un-protonated** form of a weak base can be absorbed

Answer 34

un-protonated because it will be uncharged and therefore will be hydrophobic

Question 35

a weak base tends to become **charged/uncharged** at lower pHs

Answer 35

charged

Question 36

example of a weak base drug

Answer 36

lidocaine

Question 37

a weak acid tends to become **charged/uncharged** at higher pHs

Answer 37

charged

Question 38

example of weak acid drug

Answer 38

ibuprofen

Question 39

Henderson-Hasselbalch equation

Answer 39

allows you to calculate the ratio of charged to uncharged of a drug at a given pH; de-protonated/ protonated [A-]/[HA] = 10 ^ (pH-pka) [B]/[HB+] = 10 6 (pH-pka)

Question 40

Weak acid equation

Answer 40

HA --\> H+ + A-

Question 41

Weak base equation

Answer 41

HB+ --\> H+ + B

Question 42

ph \< pKa for a weak acid

Answer 42

more absorbable

Question 43

ph \> pka for a weak base

Answer 43

more absorbable

Question 44

pka value **does/does not** tell you whether the drug is a weak acid or base

Answer 44

does not; only the molecular shape

Question 45

**T/F** some drugs are both weak acids and weak bases depending on pKa value

Answer 45

true

Question 46

pharmacodynamics

Answer 46

(PD) how a drug molecule affects its target to produce the desired physiological effect

Question 47

absorption

Answer 47

the first pharmacokinetic phase: How does a druge get into the body?

Question 48

distribution

Answer 48

second phase of pharmacokinetics; how does the drug get to the target site?

Question 49

metabolic

Answer 49

third stage of pharacokinetic; how is a drug molecule chemically altered by the body?

Question 50

clearance

Answer 50

Fourth phase of pharmacokinetics; how does the drug get cleared/removed from the body?

Question 51

three factors that affect absorption

Answer 51

1. surface area 2. drug transit time (how long the drug spends in the area) 3. pH of the lumen

Question 52

Which organ is the primary site of absoprtion and why?

Answer 52

small intestine because increased surface are slow transit time neutral pH

Question 53

What is the best organ for absorbing acidic drugs?

Answer 53

stomach

Question 54

**T/F** Drugs must pass through four layers of lipid bilayers if they are going to pass through epithelial and enotheilial cells

Answer 54

T

Question 55

the rates of ________ and ________ are limited by the amount of transport protein present meaning they can become \_\_\_\_\_\_\_

Answer 55

facilitated diffusion active transport saturated/saturable

Question 56

two types of passive transport

Answer 56

1. Diffusion 2. Facilitated diffusion do not require energy

Question 57

the type of absorption that is non-saturable

Answer 57

diffusion - passive transport

Question 58

**weak bases/weak acids** will be better absorbed in the stomach

Answer 58

weak acids

Question 59

weak bases/weak acids will be better absorbed in the small intestine

Answer 59

weak bases

Question 60

bioavailability definition

Answer 60

the fraction of drug dose that reaches the systemic circulation (plasma)

Question 61

bioavailability of IV drug

Answer 61

100%

Question 62

**T/F** Bioavailability of a drug differs depending on the route of administration

Answer 62

T

Question 63

bioavailability equation

Answer 63

Area under the curve (AUC) = (AUC(oral))/(AUC(IV))

Question 64

the bioavailabilty is measured after what effect

Answer 64

"first pass effect" = metabolic reactions in the liver

Question 65

some oral drugs may be degraded by intestinal bacteria which would **decrease/increase** absorption and bioavailability

Answer 65

decrease

Question 66

most drugs must reach the ______ in order to be distributed effectively

Answer 66

circulation system/ blood/plasma

Question 67

oral drugs are subject to the first pass effect that **increases/decreases** the drugs bioavailabilty

Answer 67

decreases

Question 68

drug binding to serum proteins affects which two phases of pharmacokinetics

Answer 68

distribution and clearance

Question 69

If Vd is 0.6 L/kg where is the drug located

Answer 69

all compartments ex. ethanol

Question 70

Vd or volume of distribution is important for calculating

Answer 70

drug half life loading dose rate of drug clearance

Question 71

xenobiotics

Answer 71

toxin or drugs

Question 72

which liver enzymes are largely responsible for chemical degradation /modifcation of xenobiotics via Phase I and Phase II

Answer 72

cytochrome p450

Question 73

drugs are usually metabolized in order to **active/inactive them**, and to facilitate their elimination via urine or feces

Answer 73

inactivate

Question 74

two phases of clearance

Answer 74

Phase I : functional phase Phase II: congucational phase

Question 75

through the phases the drug molecule becomes more **nonpolar/polar** and **smaller/larger**

Answer 75

polar and larger

Question 76

Phase I Clearance Reactions

Answer 76

Functional Phase can be oxidation, reduction, hydrolysis

Question 77

Phase II Clearance Reactions

Answer 77

Conjugation Phase Glucuronidation, acetylation, methylation, sulfation, glycine, glutathione

Question 78

What class of enzyme is responsible for functional phase metabolism of xenobiotics?

Answer 78

cytochrome p450 (CYP families 1, 2, and 3

Question 79

What type of enzyme is responsible for phase II metabolism of clinically realted drugs?

Answer 79

transferases ex. UDP-glucouronosyltrnsferase N-acetyl- p- aminophenol

Question 80

What happens when a drug is metabolized via multiple mechanisms?

Answer 80

different percentages will be processed via each pathway

Question 81

In some cases, phase I reactions are necessary to convert a pro-drug to its ACTIVE form... provide one example.

Answer 81

Clopidogrel (plavix)

Question 82

enterohepatic circulation

Answer 82

allows metabolized drugs to be reabsorbed

Question 83

antibiotics role in enterohepatic circulation

Answer 83

antibiotics can block this effect

Question 84

how does enterohepatic circulation affect half-life of some drugs?

Answer 84

increases the half-life becuase some drugs will become reabsorbed after being metabolized

Question 85

example of a drug interaction that affects absorption

Answer 85

ex. omeprazole and cefpodoxime ex. digoxin and antibiotics

Question 86

example of drug interactions that involve changes in distribution

Answer 86

ex. NSAIDS and Warfarin

Question 87

Drug- drug interactions that involve changes in metabolism

Answer 87

many drugs inhibit or induce the CYP enzyme systems therefore many drugs interact with each other through their effects on CYP enzymes ex. omeprazole inhibits CYP enzyme that acts on clopidogrel

Question 88

drug-drug interactions that invovle changes in clearance

Answer 88

Question 89

four patient categories that affect pharmacokinetic

Answer 89

1. age 2. body composition 3. health status 4. genetic profile

Question 90

Polymorphisms (genetic variation) among individuals can greatly affect a drug's pharmocokinetics. Provide and example.

Answer 90

p-glycoprotein (transmembrane protein that pumps drugs out of cells)

Question 91

polymorphisms in CYP genes lead to individual variations in \_\_\_\_\_

Answer 91

drug metabolism