V 1 B 1

Front 1

What is a dose response curve?

Back 1

it is a curve that depicts the relationship between the dose of the drug administered (X axis) and the resulting pharmacologic effect (Y axis.)

Front 2

List four descriptive characteristics of the dose response curve, by which dose response curves are characterized differently:

Back 2

potency.

slope.

efficacy.

individual variability.

Front 3

Describe how potency of the drug is depicted on the dose response curve?

Back 3

potency is depicted by its location along the dose axis (usually the x axis.)

Front 4

What effect does increased affinity of the drug for its receptor site shift the dose axis on the dose response curve?

Back 4

to left.

decreased affinity shift the curve to the right.

Front 5

What is the relationship seen between drug potency and receptor affinity?

Back 5

they are directly related. The more potent the drug, a greater the affinity for its receptor.

Front 6

What does the slope of a dose response curve revealed about the drug?

Back 6

it indicates the number of receptors that must be occupied before the drug effect occurs.

Front 7

What does steep dose response curve indicate about the drug?

Back 7

it means that a majority of the receptors must be found before a relevant effect occurs.

Front 8

How steep is the dose response curve with neuromuscular blocking drugs?

what does this indicate?

Back 8

it is steep.

this indicates that a majority of receptors must be occupied before there is an effect.

Front 9

Define drug efficacy:

Back 9

it is a measure of the intrinsic ability of the drug to produce a given physiologic or clinical affect.

the maximal effect of the drug reflects intrinsic activity or efficacy.

Front 10

Where on the dose response curve is efficacy depicted?

Back 10

on the plateau.

a higher plateau correlates with greater efficacy.

Front 11

Describe how the presence of competitive antagonists would alter the dose response curve:

Back 11

it would shift the curve to the right, with no change in the efficacy (plateau) or slope.

the rightward shift is caused by competition for the same number of receptors.

Front 12

Describe how the presence of a noncompetitive antagonists would alter the dose response curve of the drug:

Back 12

it would shift the curve rightward and downward, with a decrease in the slope of the curve.

this is because the maximal effect cannot be achieved in the presence of the noncompetitive block. In other words, a noncompetitive block cannot be reversed by excess agonist.

Front 13

What is LD50/ED 50?

Back 13

it is the therapeutic index.

it is LD50 divided by ED 50.

TI equals LD50/ED 50.

Front 14

What is LD50?

Back 14

the median lethal dose of a drug.

Front 15

what is ED 50?

Back 15

the median effective dose of a drug.

Front 16

A patient who is allergic to one drug is also allergic to another related drug. What is this phenomenon called?

Back 16

cross sensitivity or cross reactivity.

patient may be cross sensitive to structurally similar drugs.

Front 17

The patient is known to be allergic to penicillin. This patient is likely to have cross sensitivity to what other group of antibiotics?

why?

Back 17

cephalosporins.

this is because penicillins and cephalosporins both have a beta lactam ring.

Front 18

Is there cross sensitivity among ester local anesthetics?

why?

Back 18

yes.

this is because they have a common metabolite, para amino benzoic acid (paba.)

Front 19

Is there cross sensitivity between ester and amide local anesthetics?

Back 19

no.

Front 20

Can a patient with analogy to an ester local anesthetic receive an amide local anesthetic?

Back 20

yes.

can a patient with an allergy to an amide local anesthetic receive an ester local anesthetic?

Front 21

write an equation that shows how the volume of distribution is calculated:

Back 21

Vd = Q/Cp

Vd is volume of distribution.

Q is the quantity of drug injected.

Cp is the plasma concentration of the drug that will be achieved if the drug distributed instantaneously within is volume of distribution after its injection.

Front 22

What is the elimination half time of the drug?

Back 22

the time it takes for the plasma concentration to decreased by one half.

Front 23

What two factors determine elimination half time?

Back 23

volume of distribution (directly related to halftime.)

clearance (Cl, is inversely related to halftime.

Front 24

Mathematically, what does T 1/2 equal?

Back 24

Vd/Cl.

Front 25

A substance with what clearance (large or small) and what volume of distribution (large or small) will have the longest halftime elimination?

Back 25

half time elimination is greater if volume of distribution is large and/or clearance is small.

Front 26

A drug is eliminated by first order kinetics. Four grams. Five hours later, 2 g have been metabolized.

after 10 more hours, how much more is metabolized?

Back 26

1.5 g.

the half life is five hours because the amount of drug decreased from 4 g to 2 g in five hours.

in the next five hours, 1 g is lost in five hours later another 0.5 g is lost.

Front 27

In first order kinetics, how much of the drug is gone after one half life?

Back 27

one half.

Front 28

If the drug is excreted by first order kinetics, how long will it take for the plasma concentration to fall 50 mg if the half life is 20 hours and 200 mg was administered?

Back 28

40 hours.

in first order kinetics, a plasma concentration decreases by one half during each half life. The concentration dropped from 200 mg to 100 mg in the first 20 hours (one half life) and from 100 mg to 50 mg in the next 20 hours.

Front 29

If 60 mg of the drug is given and 15 mg remained after 12 hours, how much drug is eliminated in the next 12 hours?

Back 29

11.25 mg.

the half life is six hours (decreased from 60 to 30 in six hours and from 30 to 15 in the next six hours.)

half the remaining 15 mg (7.5 mg) will be excreted in the next six hours, and then one half of 7.5 mg (3.75 mg) will be excreted in the following six hours.

thus, 7.5 mg +3.75 mg equals 11.25 mg to be excreted in the next 12 hours.

Front 30

Diffusion of the drug across a membrane is proportional to the concentration gradient. Diffusion is also dependent on what three factors?

Back 30

solubility of the drug in lipid.

thickness of the membrane.

molecular weight of the drug (the larger the molecular weight, the slower the rate of diffusion.)

Front 31

The degree of protein binding of a drug in the blood is dependent upon what primary factor?

Back 31

the total amount of protein in the blood.

the amount of drug bound to protein will change when plasma protein levels change.

Front 32

What is the most important plasma protein providing of drugs ?

Back 32

albumin.

Front 33

Rank the following routes of administration, from greatest to least, with regards to peak plasma concentration:

subcutaneous, intravenous, caudal epidural, intrathecal:

Back 33

intravenous> intrathecal> caudal epidural> subcutaneous.

Front 34

Identify the most important determinant of the buildup of intravenous agent in a given tissue:

Back 34

blood flow to the tissue.

Front 35

Besides blood flow, what two other factors determine the amount of intravenous anesthetic going into and out of a tissue compartment?

Back 35

lipid solubility and degree of ionization in plasma.

Front 36

Drugs that are absorbed from the gastrointestinal tract must first pass through which organ before reaching general circulation?

Back 36

the liver, via the portal circulation.

Front 37

Drugs that are absorbed from the gastrointestinal tract may be metabolized to some extent by the liver before reaching the general circulation. What does this affect called?

Back 37

first pass effect.

Front 38

What is an acid?

Back 38

a hydrogen ions or proton donor.

Front 39

Why is a substance called a weak acid?

Back 39

because it does not ionized 100% in solution.

Front 40

Why is a substance called the strong acid?

Back 40

because it ionizes 100% in solution.

example: HCl.

Front 41

Why is carbonic acid considered a weak acid?

Back 41

because carbonic acid ionizes only 0.2% in physiologic solution.

an acid that does not dissociate 100% to its ionized form is a weak acid.

Front 42

What agents used in anesthesia are weak acids?

Back 42

barbiturates.

Front 43

What happens to the amount of weak acid in not ionized form as pH falls?

what is the amount ionized?

Back 43

as pH decreases, the amount of weak acid in non ionized form increases.

Front 44

What is the rule with weak acids in solutions when pH either increases or decreases?

Back 44

plus acid equals more nonionized.

as pH decreases, or is nonionized.

if pH increases, more of the weak acid in ionized form increases.

Front 45

A weak acid with a 7.8 will be more than 50% or less than 50% nonionized at pH 7.4?

Back 45

more than 50%.

Front 46

What happens when a weak acid is injected into an acidotic patient?

Back 46

more drug is nonionized.

as pH decreases, the nonionized fraction increases.

acid plus acid equals nonionized.

Front 47

How much barbiturate crosses the blood brain barrier when you give it to a patient with low pH, more or less?

explain:

Back 47

more. Barbiturate is nonionized at lower pH, so greater amounts cross the blood brain barrier.

Front 48

Propofol, a weak acid, has pKa of 11. His propofol mostly ionized or mostly unionized that normal physiologic pH of 7.4?

explain:

Back 48

since the normal physiologic pH of 7.4 is less than the PKa 11 of propofol, the body environment is an acidic environment for the weak acid propofol.

acid plus acid equals more nonionized. Therefore, propofol but mostly nonionized at 7.4.

Front 49

What agents used in anesthesia are weak basis?

Back 49

all local anesthetics.

all opioids.

etomidate.

ketamine.

Front 50

What happens to the amount of a weak base in ionized form as pH decreases?

Back 50

it increases. Rule: base plus acid equals more ionized.

Front 51

What happens to the amount of a weak base in ionized form as pH increases?

Back 51

it decreases.

rule: base plus base equals more nonionized.

Front 52

A weak base with a PK of 7.8 will become more than 50% or less than 50% nonionized at pH 7.4?

Back 52

less than 50% nonionized.

Front 53

During resuscitation, intravenous access is not or cannot be established, what route of administration can result in high peak plasma drug levels?

Back 53

endotracheal.

it is almost identical to intravenous.

Front 54

What happens when a weak base is administered to an acidotic patient?

Back 54

less drug is nonionized.

rule, base plus acid equals more ionized.

Front 55

Do drugs that are weak acids form salts with positive ions such as sodium or negative ions such as sulfate or chloride?

Back 55

drugs that are weak acids form salts with positive ions (sodium, potassium, calcium, magnesium.)

sodium pentobarbital is an example of a weak acid. A drug is a weak acid if it forms a salt with a positive ion.

Front 56

Do drugs that are weak bases form salts with positive ions such as sodium or negative ions such as sulfate or chloride?

Back 56

drugs that are weak bases form salts with negatively charged ions (chloride, sulfate, phosphate.)

Front 57

Give two examples of commonly used drugs that are weak bases:

Back 57

lidocaine and morphine sulfate.

Front 58

?

Back 58

more than 50% ionized.

sulfate equals weak base.

the key to solving this problem is determining if you are dealing with a weak acid or a weak base.

Front 59

A new drug, sodium X., has a pKa of nine. Will this drug to be more than 50% ionized, 50% ionized, or less than 50% ionized abnormal body pH of 7.4?

Back 59

less than 50% ionized.

sodium x is a weak acid.

Front 60

Our morphine, meperidine, fentanyl, and sufentanil more than 50% nonionized or less than 50% nonionized at pH 7.4?

explain:

Back 60

they will be less than 50% nonionized.

opioids are weak bases.

Front 61

are alfentanil and remifentalil more than 50% nonionized or less than 50% nonionized at pH 7.4?

explain:

Back 61

there will be more than 50% nonionized at pH 7.4. Their pH's are 6.5 and 7.26, respectively.

Front 62

?

Back 62

more than 50% ionized.

sulfate equals weak base.

the key to solving this problem is determining if you are dealing with a weak acid or a weak base.

Front 63

?

Back 63

more than 50% ionized.

sulfate equals weak base.

the key to solving this problem is determining if you are dealing with a weak acid or a weak base.

Front 64

A new drug, sodium X., has a pKa of nine. Will this drug to be more than 50% ionized, 50% ionized, or less than 50% ionized abnormal body pH of 7.4?

Back 64

less than 50% ionized. -- sodium x is a weak acid.