Pharmacokinetics 2

Question 1

In which circumstance is a drug MORE likely to pass through a lipid membrane?
a. a weak base where the pH of the solution is > the pKa of the drug
b. a weak base where the pH of the solution is < the pKa of the drug
c. a weak acid where the pH of the solution is < the pKa of the drug
d. a weak acid where the pH of the solution is > the pKa of the drug

Answer 1

A & C

Question 2

Ionization describes the process where

Answer 2

a molecule gains a positive or negative charge; this affects a molecule’s ability to diffuse through lipid membranes

Question 3

A drug’s pKa equals the pH where

Answer 3

50% of the drug is ionized and the other 50% of the drug is non-ionized

Question 4

Ionization affects a drug’s

Answer 4

pharmacologic activity as well as its ability to pass through cell membranes

Question 5

A drug that’s a weak acid will

Answer 5

donate a proton to water (pH = 7)

Question 6

A drug that’s a weak base will

Answer 6

accept a proton from water (pH= 7)

Question 7

An acid is a substance that

Answer 7

donates a proton
HA+ <–> H+ + A

Question 8

A base is a substance that

Answer 8

accepts a proton
B- +H+ <–> BH

Question 9

The pH measures the concentration of

Answer 9

hydrogen ions in an aqueous solution

Question 10

If you put a strong acid or a strong base in water, it will

Answer 10

dissociate completely

Question 11

If you put a weak acid or a weak base in water,

Answer 11

a fraction will ionize, and the remaining fraction will be non-ionized

Question 12

Ionization is dependent on the following two factors:

Answer 12

the pH of the solution
the pKa of the drug

Question 13

The pKa tells us how much

Answer 13

a molecule wants to behave like an acid
low pKa= amazing acid
high pKa= terrible acid

Question 14

In an acidic solution, weak bases are

Answer 14

more ionized and water-soluble

Question 15

In a basic solution, weak bases are

Answer 15

more non-ionized and lipid-soluble

Question 16

In an acidic solution, weak acids are

Answer 16

more non-ionized and lipid-soluble

Question 17

In a basic solution, weak acids are more

Answer 17

ionized and water-soluble

Question 18

A weak acid is paired with a positive ion such as

Answer 18

sodium, calcium, or magnesium

Question 19

A weak base is paired with a negative ion such as

Answer 19

chloride or sulfate

Question 20

Describe the solubility of an ionized drug

Answer 20

water soluble- hydrophilic, liphophobic

Question 21

Describe the diffusion of an ionized drug across lipid bilayers.

Answer 21

does not diffuse across blood-brain barrier, GI tract, and placenta

Question 22

Does an ionized drug have an active or inactive pharmacologic effect?

Answer 22

not active

Question 23

Describe hepatic biotransformation and renal elimination for an ionized drug.

Answer 23

hepatic biotransformation- less likely
renal elimination- more likely

Question 24

Describe the solubility of a non-ionized drug.

Answer 24

lipid soluble
-liphophilic
-hydrophobic

Question 25

Describe the pharmacologic effect on a non-ionized drug.

Answer 25

active

Question 26

Describe the diffusion across lipid bilayers for a non-ionized drug.

Answer 26

diffuses across blood-brain barrier, GI tract, & placenta

Question 27

Describe the hepatic biotransformation and renal elimination of a non-ionized drug.

Answer 27

hepatic biotransformation- more likely renal elimination- less likely

Question 28

Which circumstance creates the STRONGEST gradient for the passage of local anesthetic from the mother to the fetus? a. maternal acidosis and fetal acidosis b. maternal acidosis and fetal alkalosis c. maternal alkalosis and fetal acidosis d. maternal alkalosis and fetal alkalosis C.

Answer 28

C.- maternal alkalosis and fetal acidosis

Question 29

Fetal pH is typically _____ than maternal pH

Answer 29

lower

Question 30

Lower fetal pH can lead to

Answer 30

ion trapping and increased fetal drug concentrations

Question 31

The combination of ________ & __________ worsens the problem of ion trapping in the fetus.

Answer 31

maternal alkalosis & fetal acidosis

Question 32

Of the commonly used anesthetics for neuraxial anesthesia, _______ is most likely to undergo fetal ion trapping.

Answer 32

lidocaine

Question 33

Of the commonly used anesthetics for neuraxial anesthesia, _________ is least likely to undergo fetal ion trapping.

Answer 33

chloroprocaine

Question 34

If a drug is 98% bound by plasma protein, and the bound fraction decreases to 96%, the free fraction will increase by

Answer 34

100

Question 35

Plasma proteins include

Answer 35

albumin, alpha 1-acid glycoprotein, and beta-globulin

Question 36

Albumin primarily binds with

Answer 36

acidic drugs

Question 37

Alpha 1-acid glycoprotein and beta-globulin typically bind with

Answer 37

basic drugs

Question 38

These conditions can decrease protein concentrations

Answer 38

liver disease, renal disease, old age, malnutrition, and pregnancy

Question 39

_______ synthesizes plasma proteins

Answer 39

The liver

Question 40

A drug bound to a plasma protein cannot

Answer 40

bind to a receptor nor can it be cleared by a clearing organ

Question 41

The extent of plasma protein binding affects the

Answer 41

intensity of drug effect effect and the drug's duration of action

Question 42

The most plentiful plasma protein is

Answer 42

albumin

Question 43

Albumin is decreased by

Answer 43

liver disease renal disease old age malnutrition and pregnancy

Question 44

Alpha 1 acid glycoprotein concentration is increased by

Answer 44

surgical stress myocardial infarction chronic pain rheumatoid arthritis advanced age

Question 45

Alpha 1 acid glycoprotein concentration is decreased by

Answer 45

neonates pregnancy

Question 46

The percent increase formula is:

Answer 46

percent change= ((new value- old value)/old value)) x 100% positive result= increase negative result= decrease

Question 47

Changes in protein binding can result from

Answer 47

decreased plasma protein content or competition for binding sites on the protein

Question 48

Factors that decrease plasma protein include

Answer 48

reduced synthetic function (liver disease, malnutrition) altered distribution (3rd trimester of pregnancy) increased protein excretion (renal disease)

Question 49

The volume of distribution is ______- related to the degree of plasma protein binding

Answer 49

inversely

Question 50

Highly protein-bound drugs typically have a ______ rate of metabolism and elimination

Answer 50

slower

Question 51

The risk of adverse effects is greatest when a drug has a

Answer 51

narrow therapeutic index

Question 52

Alterations in plasma protein binding can be a problem in several situations such as during

Answer 52

CPB (hemodilution and heparinization) as well as in ECMO circuits

Question 53

Which kinetic model describes the process that metabolizes a constant amount of drug per unit time? a. zero order b. first order c. second order d. third order

Answer 53

a. zero order

Question 54

Describe zero order kinetics.

Answer 54

constant amount of the drug is metabolized per unit time

Question 55

Describe first order kinetics.

Answer 55

constant fraction of the drug is metabolized per unit time