Pharm Ii (Mod, Test #1)- Set 1

Front 1

What is pharmacodynamics?

Back 1

What a drug does in the body: biochemical, physiological, and behavioral effects of drugs

Front 2

Mechanism of drug action is influenced by?

Back 2

1. Structure-activity relationships
2. Receptors and signaling mechanisms

Front 3

What curve demonstrates the mechanism of drug action?

Back 3

Dose-response curve

Front 4

What is pharmacokinetics?

Back 4

What the body does to a drug over time

Front 5

Pharmacokinetics can also be defined as?

Back 5

Quantitative study of the absorption, distribution, and clearance (metabolism and excretion) of drugs and drug metabolites

Front 6

What determines the PLASMA DRUG CONCENTRATION (Cp)?

Back 6

Absorption, distribution, and clearance at any time after drug administration

Front 7

For many drugs, the intensity and duration of drug effects (therapeutic and toxic) are related to the?

Back 7

Cp (plasma drug concentration)

Front 8

What occurs to maintain therapeutic Cp and avoid toxic levels?

Back 8

Selection and adjustment of drug dosage schedules

Front 9

What determines Cp?

Back 9

rate and extent of drug absorption

Front 10

Oral administration is the?

Back 10

safest and most comon route; also the most convenient and economical route

Front 11

With oral administration where does the absorption mainly occur?

Back 11

in the small intestine

Front 12

Absorption of oral medications is usually demonstrated by this process?

Back 12

first-order process

Front 13

Controlled release medications demonstrate this process?

Back 13

zero-order process

Front 14

What are some disadvantages of oral adminstration?

Back 14

irritation of GI tract; irregular absorption; inactivation of drug by enzymes, bacteria, low gastric pH, and FIRST-PASS ELIMINATION

Front 15

First-pass elimination

Back 15

drug in the venous blood leaving the GI tract is directed via the hepatic portal vein to the liver and some drugs which are avidly extracted by the liver may attain very low circulating levels after oral administration, compared to levels attained after parenteral administration

Front 16

Bioavailability (F)

Back 16

fraction of an orally (or parenterally) administered drug available to produce a pharmacological effect

Front 17

Sublingual administration is useful for?

Back 17

nonionized, highly lipid-soluble drugs (eg, nitro)

Front 18

What are some benefits to sublingual administration?

Back 18

rapid absorption and no first-pass elimination

Front 19

Subcutaneous administration

Back 19

provides for relatively slow and constant absorption and sustained therapeutic Cp; may minimize adverse drug effects

Front 20

With subcutaneous administration, absorption is limited in part by?

Back 20

blood flow to site of administration

Front 21

Pulmonary administration

Back 21

useful for gaseous and volatile agents and aerosols, rapid absorption

Front 22

With pulmonary administration why is there rapid absorption?

Back 22

1. Large alveolar surface area
2. Thin alveolar membranes
3. High rate of blood flow

Front 23

Name 3 other routes involving absorption

Back 23

1. Intramuscular
2. Rectal
3. Transdermal

Front 24

Does intramuscular administration have a rapid or slow rate of absorption?

Back 24

rapid

Front 25

Rectal administration

Back 25

some first-pass elimination may occur depending on location of drug in rectum

Front 26

Transdermal

Back 26

very slow absorption; prolonged duration of action

Front 27

Intravenous administration

Back 27

Technically does not involve absorption; F=100%

Front 28

What are some benefits to IV administration?

Back 28

1. Rapid and precise attainment of Cp
2. May be useful for administration of irritant drugs and solutions; drug is rapidly diluted

Front 29

What are some disadvantages of IV administration?

Back 29

Increased risk of adverse effects (high Cp attained rapidly; possible toxicity, risk of embolism)

Front 30

Compartment modeling

Back 30

consider the body to be comprised of one or more compartments; each compartment represents a theoretical "space", not some actual anatomical region

Front 31

Compartment modeling provides...

Back 31

a mathematical description of drug disposition

Front 32

One-compartment model

Back 32

Conceptually simple, but not sufficient to describe the pharmacokinetic behavior of most drugs

Front 33

Two-compartment model

Back 33

Drug introduced via IV injection into a central compartment and eventual distribution of drug to peripheral compartment until equilibrium is reached btwn 2 compartments

Front 34

What is included in the central compartment?

Back 34

Intravascular fluid and highly perfused tissues such as the heart, brain, liver, kidneys, lungs and blood

Front 35

These tissues in the central compartment make up only 10% of body mass, but receive what percentage of CO?

Back 35

75% of resting CO

Front 36

The lungs receive how much of the cardiac output of the right side of the heart?

Back 36

100%

Front 37

What tissues are included in the peripheral compartment?

Back 37

tissues with lower perfusion rates, primarly muscle and fat (together ~ 70% of body mass)

Front 38

Apparent volume of distribution (Vd)*

Back 38

estimates the extent of distribution of a drug in the body

Front 39

Vd=

Back 39

Dose/Cp

Front 40

Plasma concentration of the drug is at the point of?

Back 40

distribution equilibrium C1=C2

Front 41

Body compartment volumes

Back 41

volume
compartment L/70kg L/kg
TBW 42 0.6
ECF 14 0.2
Plasma 2.8 0.04

Front 42

Plasma concentration-time curves plot?

Back 42

the rate of change of Cp

Front 43

With the plasma concentration-time curves there are two distinct phases, what are they?

Back 43

1. Distribution (alpha) phase
2. Elimination (beta) phase

Front 44

Distribution (alpha) phase

Back 44

begins immediately after IV injection of drug and represents distribution of drug from central compartment to peripheral compartment; EXPONENTIAL DECLINE in Cp (first-order process)

Front 45

Elimination (beta) phase

Back 45

1. Exponential decline in Cp (first-order kinetics)
2. Constant fraction of drug is eliminated from the central compartment per unit time (eg, 10% per hour)
3. Most drugs are eliminated from the central compartment by first-order kinetics

Front 46

Cp=

Back 46

Ae(-alpha(t)) + Be (-beta(t))

Front 47

alpha =

Back 47

the distribution rate constant

Front 48

beta=

Back 48

the elimination rate constant, the SLOPE of the elimination phase of the curve

Front 49

Use of the concentration-time curve to determine?

Back 49

Vd

Front 50

Protein binding of drugs

Back 50

many drugs can bind to plasma proteins, and many are highly (>90%) protein-bound in the blood

Front 51

Albumin binds mainly?

Back 51

acidic drugs, such as barbituates

Front 52

alpha1-acid glycoprotein (AAG) binds mainly?

Back 52

basic drugs, such as local anesthetics

Front 53

What exists between the bound and free drug fractions?

Back 53

an equilibrium

Front 54

What is the active fraction?

Back 54

the free fraction

Front 55

Vd is inversely related to?

Back 55

the degree of plasma protein binding

Front 56

Drug clearance may also be influenced by?

Back 56

protein binding

Front 57

Drugs may ______ with each other or with endogenous substances for protein binding sites.

Back 57

compete

Front 58

This competition may?

Back 58

exaggerate of enhance the response of the drug

Front 59

What causes decreased plasma proteins or with decreased binding affinity of plasma proteins for drugs?

Back 59

some disease states such as liver disease or uremia (anything that reduces the amount of protein, eg, burns)

Front 60

What may occur with decreased plasma proteins if a drug is normally highly protein bound (free fraction < 10%)?

Back 60

May cause an exaggerated drug effect, though this may be of clinical significance only for rapidly acting drugs that are administered acutely (eg, versed)

Front 61

What may occur with decreased plasma proteins if a drug is only moderately protein bound?

Back 61

changes in protein binding will likely be clinically unimportant, even for rapidly acting drugs; for example, if the free fractionof a drug increases from 50-60% for a particular drug dose, the plasma concentration of free drug will increase at most by 1/5 or 20%, which will likely be clinically insignificant

Front 62

Drug clearance

Back 62

the ratio of the rate of drug eliminated by all routes to the plasma drug concentration

Front 63

CL=

Back 63

rate of elimination/Cp

Front 64

What are the units of CL?

Back 64

volume per time (min/mL)

Front 65

What are the two main sites of drug elimination?

Back 65

liver and kidneys; other sites include the lung and blood

Front 66

hepatic clearance

Back 66

biotransformation and/or excretion of unchanged drug in the bile

Front 67

renal clearance

Back 67

excretion of unchanged drug in the urine

Front 68

For most drugs, clearance is a _____ process?

Back 68

first order process

Front 69

In first order process, rate of elimination is proportional to?

Back 69

amount of drug present

Front 70

CL is independent of?

Back 70

drug dose

Front 71

As Cp increases, so does the?

Back 71

rate of elimination

Front 72

CL is not?

Back 72

saturable over the range of therapeutic plasma levels

Front 73

For some drugs, clearance is?

Back 73

capacity-limited

Front 74

Synonyms to capacity-limited.

Back 74

zero-order process; dose-dependent clearance; nonlinear kinetics

Front 75

CL does depend on?

Back 75

dose (rate of elimination stays constant despite an increase in Cp)

Front 76

elimination pathways are?

Back 76

saturable

Front 77

T or F. in capacity-limited clearance a constant amount of drug is eliminated per unit time.

Back 77

True

Front 78

What are some examples of drugs that undergo zero-order kinetics of elimination?

Back 78

ethanol, ASA, phenytoin

Front 79

Elimination half-time, t1/2 (plasma half-life)

Back 79

amount of time necessary for Cp to fall by 50%; estimate of the rate of elimination of the drug by the body

Front 80

For a first-order process: t1/2 =

Back 80

0.69/beta, where beta=elimination rate constant (fraction of drug eliminated per hour)

Front 81

t1/2=

Back 81

0.69 x Vd/CL

Front 82

How many half-times are necessary for almost complete elimination of a drug (~97%)?

Back 82

5 times

Front 83

Where is t1/2 most useful?

Back 83

in the design of drug dosage schedules