Drug Excretion

Question 1

______ introduce a strong polar center into the molecule and increase its molecular weight.

Answer 1

Conjugates

Question 2

Many drugs (usually of high molecular weight) are excreted into ____, but these are usually reabsorbed from the small intestine and then eliminated in the _____, rather than the feces.

Answer 2

bile; urine

Question 2

Drug metabolites are secreted into the ____ where they can then be hydrolyzed by bacterial enzymes back to ______ and undergo reabsorption from the gut.

Answer 2

bile; the parent drug

Question 3

Drugs cleared by the kidneys have t1/2 of ____ (but extensive protein binding can prolong t1/2).

Answer 3

1-4 hrs

Question 4

What does active tubular secretion mean?

Answer 4

drugs are transported directly from blood into urine

Question 4

Due to ______, drugs that are lipid-soluble and uncharged would be cleared at the rate of urine formation (1 ml/min).

Answer 4

tubular reabsorption

Question 5

______ can be cleared at rate of 120-600 ml/min.

Answer 5

Actively secreted drugs

Question 6

What is the half life of drugs filtered by active tubular secretion?

Answer 6

1-2 hours

Question 7

_____ occurs with lipid soluble molecules in proximal and distal tubules.

Answer 7

Passive diffusion

Question 7

What reduces the elimination of drug and prolongs its half-life and duration of action in the body?

Answer 7

the enterohepatic cycle

Question 8

Many drugs (usually of ______) are excreted into bile, but these are usually reabsorbed from the ______ and then eliminated in the urine, rather than the feces.

Answer 8

high molecular weight; small intestine

Question 9

How does plasma protein binding affect the rate of secretion in active tubular secretion?

Answer 9

it doesn’t

Question 10

Name 3 acidic drugs that are excreted via active tubular secretion.

Answer 10

Penicillins, salicylate, diuretics

Question 11

Drug elimination by zero-order kinetics means that _______.

Answer 11

it’s cleared at a constant rate no matter the concentration

Question 12

Drug clearance by _____ occurs at rate of 120 ml/min.

Answer 12

glomerular filtration

Question 12

What is the outcome of the enterohepatic cycle?

Answer 12

it reduces the elimination of drug and prolongs its half-life and duration of action in the body

Question 12

_____ that reduce gut bacterial flora can decrease enterohepatic recycling and decrease plasma drug levels.

Answer 12

Antibiotics

Question 12

Milk is more _____ than plasma; therefore tendency to accumulate _____ compounds by ion-trapping.

Answer 12

acidic; basic

Question 13

Actively secreted drugs can be cleared at rate of ______.

Answer 13

120-600 ml/min

Question 14

Due to tubular reabsorption, drugs that are lipid-soluble and uncharged would be cleared at the _______.

Answer 14

rate of urine formation (1 ml/min)

Question 15

A primary function of ______ is production of a more water soluble metabolite that is less likely to be reabsorbed.

Answer 15

drug metabolism

Question 16

______ can be limited by desynchronizing breastfeeding and peak milk drug concentrations.

Answer 16

Infant exposure to maternal drugs

Question 18

Active tubular secretion occurs in the proximal convoluted tubule and is _____.

Answer 18

saturable

Question 19

Which drugs are excreted via active secretion?

Answer 19

strong acids and bases

Question 20

Diffusion of weak acids and bases is dependent upon \_\_\_\_\_.

Answer 20

urine pH

Question 21

\_\_\_\_\_\_ are secreted into the bile where they can then be hydrolyzed by bacterial enzymes back to the parent drug and undergo reabsorption from the gut.

Answer 21

Drug metabolites

Question 22

Passive diffusion occurs with ______ molecules in proximal and distal tubules.

Answer 22

lipid soluble

Question 23

Name 5 basic drugs that are excreted via active tubular secretion.

Answer 23

Morphine, catecholamines, histamine, hexamethonium, tolazoline

Question 24

Infant exposure to maternal drugs can be limited by \_\_\_\_\_\_.

Answer 24

desynchronizing breastfeeding and peak milk drug concentrations

Question 26

A primary function of drug metabolism is production of a more water soluble metabolite that is less likely to be \_\_\_\_\_\_.

Answer 26

reabsorbed

Question 27

A primary function of drug metabolism is production of a more ______ that is less likely to be reabsorbed.

Answer 27

water soluble metabolite

Question 28

Some drugs may have a “reservoir” of recirculating drug that can amount to about ____ of total drug present in the body.

Answer 28

20%

Question 30

Renal excretion is primarily affected by _____ and \_\_\_\_\_.

Answer 30

renal blood flow; renal function.

Question 31

Some drugs may have a “reservoir” of ______ that can amount to about 20% of total drug present in the body.

Answer 31

recirculating drug

Question 32

Active tubular secretion occurs in the _____ and is saturable.

Answer 32

proximal convoluted tubule

Question 33

Drugs can travel between cells but ____ cannot.

Answer 33

proteins

Question 34

Drug metabolites are secreted into the bile where they can then be hydrolyzed by ______ back to the parent drug and undergo reabsorption from the \_\_\_\_.

Answer 34

bacterial enzymes; gut

Question 35

Drugs cleared by the kidneys have t1/2 ≈ 1-4 hrs (but ______ can prolong t1/2)

Answer 35

extensive protein binding

Question 37

\_\_\_\_\_ occurs in the proximal convoluted tubule and is saturable.

Answer 37

Active tubular secretion

Question 39

Drug clearance by glomerular filtration occurs at rate of \_\_\_\_\_\_.

Answer 39

120 ml/min

Question 40

What is the infant plasma level for most drugs?

Answer 40

substantially below a therapeutic level (\< 5% of maternal plasma levels)

Question 41

Name 2 drugs that have a circulating reservoir.

Answer 41

morphine and ethinyl estradiol

Question 43

Active reabsorption is particularly important for \_\_\_\_\_.

Answer 43

endogenous compounds

Question 44

Milk is more acidic than plasma; therefore tendency to accumulate basic compounds by ______ .

Answer 44

ion-trapping

Question 45

In general, all drugs smaller than ______ (MW: \_\_\_\_) will be filtered.

Answer 45

albumin; 69,000

Question 46

Due to tubular reabsorption, drugs that are _____ and _____ would be cleared at the rate of urine formation (1 ml/min).

Answer 46

lipid-soluble; uncharged

Question 47

Antibiotics that reduce gut bacterial flora can decrease ______ and \_\_\_\_\_\_.

Answer 47

enterohepatic recycling; plasma drug levels

Question 48

Passive diffusion occurs with lipid soluble molecules in ______ and \_\_\_\_\_\_.

Answer 48

proximal; distal tubules

Question 49

Only free drug is filtered, NOT \_\_\_\_\_\_.

Answer 49

protein-bound

Question 50

Conjugates introduce ______ into the molecule and increase its \_\_\_\_\_\_.

Answer 50

a strong polar center; molecular weight

Question 51

Active tubular secretion is poorly developed in \_\_\_\_\_.

Answer 51

neonates