Module 5

Question 1

The removal of parent drug and drug metabolites from the body

Answer 1

Drug excretion

Question 2

What are the different sites of drug excretion?

Answer 2

Kidney, bile, lung, breast milk

Question 3

Account for the majority of drug excretion.

Answer 3

Kidneys

Question 4

Healthy kidneys serve to limit the _______ and ______ of drug effects.

Answer 4

duration

intensity

Question 5

Basic structural and functional unit of the kidney.

Answer 5

Nephron

Question 6

Carries blood into the glomerulus for filtration.

Answer 6

afferent arteriole

Question 7

Bed of capillaries that make up the first stage of filtering blood to form urine; surrounded by Bowman’s capsule

Answer 7

glomerulus

Question 8

Carries blood away from the glomerulus

Answer 8

efferent arteriole

Question 9

Essential for regulating the pH of the filtrate and is very important for the reabsorption of essential molecules such as glucose and sodium and is also an important site for drug excretion

Answer 9

PCT

Question 10

creates a concentration gradient in the medulla of the kidney; results in reasborption of water, creating a concentrated filtrate

Answer 10

loop of henle

Question 11

if water is reabsorbed in the LoH, and drugs are not, what does that mean?

Answer 11

Drugs become more concentrated in the filtrate

Question 12

Regulates electrolyte levels and filtrate pH; site of action for drugs that control BP; concentrations of drugs in the filtrate is often higher than that of blood

Answer 12

DCT

Question 13

Important site for drug reabsorption in the kidney

Answer 13

DCT - since the filtrate concentration is higher than that of the blood

Question 14

Series of tubules that connect various nephrons to the ureter; final step in the production of urine

Answer 14

Collecting duct(s)

Question 15

What are the factors affecting renal drug excretion?

Answer 15

Glomerular filtration
Tubular secretion
Tubular reasborption

Question 16

What is the major determinant of whether a drug is filtered or not?

Answer 16

Size - lipid solubility and pH do not affect glomerular filtration of drugs

Question 17

What is the force that filters drugs into the renal tubules?

Answer 17

Hydrostatic pressure within the glomerular capillaries force low MW drugs into the renal tubules

Question 18

Drug secretion primarily occurs by two transport systems. These are?

Answer 18

One for weak acids; one for weak bases

Question 19

Where are secretory transporters located in the kidney?

Answer 19

Basolateral surface (facing the blood)

Question 20

Secretion is a ______, _____ capacity process.

Answer 20

rapid, high

Question 21

After the action of the LoH, drug concentration in the filtrate is often higher than that of the surrounding blood. What type of drugs are reabsorbed?

Answer 21

Uncharged or lipid soluble drugs are able to leave the tubule and be reabsorbed back into the blood

Question 22

What is the typical GFR?

Answer 22

~120mL/min/1.73m2

Question 23

Describe the effect of age on renal function.

Answer 23

Kidney function is low in newborns (40mL/min/1.73m2)

Renal function peaks in early adulthood, and decreases with age

Question 24

If renal function is decreased, renal drug excretion is ________.

Answer 24

decreased

Question 25

Some drugs are eliminated in the bile, and ultimately excreted in the _____.

Answer 25

feces

Question 26

What are the characteristics of drugs that are excreted in the bile?

Answer 26

MW > 300Da Amphipathic Glucuronidated

Question 27

Transporters on the ________ membrane of hepatocytes transport drugs and metabolites from the liver into the bile.

Answer 27

canalicular

Question 28

___________ transports a variety of amphipathic drugs into the bile; and __________ transports glucuronidated metabolites into the bile.

Answer 28

P-glycoprotein - amphipathic | MRP2 - glucuronidated

Question 29

What are the two fates of drugs released back into the intestine from the bile?

Answer 29

Excreted in the feces | Enterohepatic recycling

Question 30

Carries blood (and drugs) from the intestine to the liver

Answer 30

portal vein

Question 31

Major cells in the liver; contain drug metabolizing enzymes

Answer 31

hepatocytes

Question 32

A thin tube that collects bile and drugs excreted by the liver

Answer 32

bile canaliculus

Question 33

Carries bile and drugs from the liver to the gallbladder, where they can then be secreted back into the intestine

Answer 33

hepatic duct

Question 34

Describe enterohepatic recycling

Answer 34

Drugs and drug conjugates get excreted in the bile, into the intestinal lumen. Intestinal bacteria cleave conjugates off the metabolites, leaving the original drug The original drug gets reabsorbed into the portal vein

Question 35

Drugs excreted by pulmonary excretion are usually ________ and/or highly ________.

Answer 35

gaseous, volatile

Question 36

What is the best example of a drug excreted by the pulmonary route?

Answer 36

general anesthetics

Question 37

Pulmonary drug excretion in different from most other excretion, how?

Answer 37

Not heavily reliant on drug metabolism

Question 38

What are factors affecting pulmonary drug excretion?

Answer 38

Rate of respiration Cardiac output Solubility of drug in blood

Question 39

Describe how drug solubility affects pulmonary excretion?

Answer 39

Low solubility in blood - high pulmonary secretion | High solubility in blood - low pulmonary excretion

Question 40

____ of women take at least one drug in the first week post-partum

Answer 40

>90%

Question 41

Drugs excreted in breast milk have what characteristics?

Answer 41

Low protein binding low MW high lipophilicity

Question 42

What transports drugs into breast milk?

Answer 42

the drug transproter BCRP - breast cancer resistance protein (active pump)

Question 43

Describe how ion trapping works in breast milk.

Answer 43

The pH of breast milk is lower than that of blood, weakly basic drugs are thus trapped there

Question 44

What are other routes of drug excretion (minor ones)?

Answer 44

Hair, saliva, sweat

Question 45

Describe the importance of drug excretion in hair.

Answer 45

Can be used to determine how long a person has been exposed

Question 46

At what rate does hair grow?

Answer 46

1cm/month

Question 47

Describe saliva drug excretion.

Answer 47

Drug excreted in saliva is usually swallowed and then subject to either intestinal absorption or fecal excretion

Question 48

Describe drug excretion through sweat.

Answer 48

drugs excreted in sweat are mostly washed away although a minor amount of dermal reabsorption may occur