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Flashcards in Module 5 Deck (48)
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1
Q

The removal of parent drug and drug metabolites from the body

A

Drug excretion

2
Q

What are the different sites of drug excretion?

A

Kidney, bile, lung, breast milk

3
Q

Account for the majority of drug excretion.

A

Kidneys

4
Q

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

A

duration

intensity

5
Q

Basic structural and functional unit of the kidney.

A

Nephron

6
Q

Carries blood into the glomerulus for filtration.

A

afferent arteriole

7
Q

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

A

glomerulus

8
Q

Carries blood away from the glomerulus

A

efferent arteriole

9
Q

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

A

PCT

10
Q

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

A

loop of henle

11
Q

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

A

Drugs become more concentrated in the filtrate

12
Q

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

A

DCT

13
Q

Important site for drug reabsorption in the kidney

A

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

14
Q

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

A

Collecting duct(s)

15
Q

What are the factors affecting renal drug excretion?

A

Glomerular filtration
Tubular secretion
Tubular reasborption

16
Q

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

A

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

17
Q

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

A

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

18
Q

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

A

One for weak acids; one for weak bases

19
Q

Where are secretory transporters located in the kidney?

A

Basolateral surface (facing the blood)

20
Q

Secretion is a ______, _____ capacity process.

A

rapid, high

21
Q

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?

A

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

22
Q

What is the typical GFR?

A

~120mL/min/1.73m2

23
Q

Describe the effect of age on renal function.

A

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

Renal function peaks in early adulthood, and decreases with age

24
Q

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

A

decreased

25
Q

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

A

feces

26
Q

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

A

MW > 300Da
Amphipathic
Glucuronidated

27
Q

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

A

canalicular

28
Q

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

A

P-glycoprotein - amphipathic

MRP2 - glucuronidated

29
Q

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

A

Excreted in the feces

Enterohepatic recycling

30
Q

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

A

portal vein

31
Q

Major cells in the liver; contain drug metabolizing enzymes

A

hepatocytes

32
Q

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

A

bile canaliculus

33
Q

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

A

hepatic duct

34
Q

Describe enterohepatic recycling

A

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

35
Q

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

A

gaseous, volatile

36
Q

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

A

general anesthetics

37
Q

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

A

Not heavily reliant on drug metabolism

38
Q

What are factors affecting pulmonary drug excretion?

A

Rate of respiration
Cardiac output
Solubility of drug in blood

39
Q

Describe how drug solubility affects pulmonary excretion?

A

Low solubility in blood - high pulmonary secretion

High solubility in blood - low pulmonary excretion

40
Q

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

A

> 90%

41
Q

Drugs excreted in breast milk have what characteristics?

A

Low protein binding
low MW
high lipophilicity

42
Q

What transports drugs into breast milk?

A

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

43
Q

Describe how ion trapping works in breast milk.

A

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

44
Q

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

A

Hair, saliva, sweat

45
Q

Describe the importance of drug excretion in hair.

A

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

46
Q

At what rate does hair grow?

A

1cm/month

47
Q

Describe saliva drug excretion.

A

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

48
Q

Describe drug excretion through sweat.

A

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