module 5

Question 1

what are the sites of drug excretion?

Answer 1

kidney
bile
lung
breast milk

Question 2

what is the role of the kidney in drug excretion?

Answer 2

-majority of drug excretion
-serve to limit the duration and intensity of drug effects

Question 3

how does decreased kidney function affect excretion?

Answer 3

decreased kidney function prolongs the duration of action and intensity of drug effects

Question 4

what is the nephron and what is its function?

Answer 4

-functional and structural unit of the kidney
-regulates water, electrolyte and drug excretion
-controls blood volume, blood pressure, blood pH and solute excretion

Question 5

what happens during glomerular filtration?

Answer 5

-drug enters the kidney from renal artery
-hydrostatic pressure forces low-weight drugs into
renal tubule
-GFR is 20% of total renal plasma flow

Question 6

what types of drugs are filtered at the glomerulus?

Answer 6

-low weight
-NON protein bound
-lipid solubility and pH do not affect filtration

Question 7

what happens to drugs during tubular secretion?

Answer 7

• drugs that were not filtered at the glomerulus can be secreted into the lumen at the proximal tubule

Question 8

what are the characteristics of secretion in the kidney?

Answer 8

-primarly occurs by two transport mechanisms (one for weak acids and one for weak bases )
-secretion is rapid high capcity process

Question 9

what are the characteristics of tubular resabsorption?

Answer 9

-occurs in DCT (allowed to happen because LOH creates a drug concrentration that is higher than the blood in the DCT

Question 10

what drugs are able to be reabsorbed in the DCT?

Answer 10

-uncharged
-lipid soluble

Question 11

what is the effect of aging on renal function

Answer 11

• newborn infants have very little renal function
  -renal function reduces with age

Question 12

what types of drugs are excreted in the bile?

Answer 12

• large molecular weight
• amphipathic molecules (polar + lipid groups)
  -glucuronidated

Question 13

how do drugs reach the bile?

Answer 13

-pgp transports a variety of amphipathic drugs into bile
-MRP2 transports glucuronidated metabolites into bile
-transporters on the canicular membrane of hepatocytes transport drugs and metabolites from liver - bile

Question 14

what is enterohepatic recycling?

Answer 14

-drugs/drugs conjugates excreted in the bile enter
intestine lumen

-intestinal bacteria can cleave the conjugate metabolites leaving the original drug

-drugs that undergo enterhepatic recycling persist in the body longer

Question 15

is pulmonary excretion reliant on drug metabolism

Answer 15

NO

Question 16

what factors effect pulmonary excretion?

Answer 16

1. Respiratory Rate
2. Cardiac Output
3. solubility of the drug in the blood

Question 17

how soluble is a drug if theres low pulomary excretion?

Answer 17

highly soluble

Question 18

what is the characteristic of a drug that has high pulmonary excretion?

Answer 18

low drug solubility

Question 19

what percent of women take a drug in the first week of post partum?

Answer 19

over 90%

Question 20

what types of drugs are excreted in breast milk?

Answer 20

1. highly lipophilic
2. low molecular weight
3. low protein binding

Question 21

what is the transporter that transports drugs into the breast

Answer 21

breast cancer resistance protein

Question 22

what can hair tell you about drug excretion?

Answer 22

determines how long the person has been exposed to the drug - hair grows 1cm per month

Question 23

what happens to saliva when it is excreted?

Answer 23

usually swallow and then subject to fecal excretion or intestinal reabsorption

Question 24

what happens when drugs are excreted through sweat?

Answer 24

drugs are mostly washed away
minor amount of dermal reabsorption can occur