Svensson Lec 4

Question 1

Name the primary routes by which drugs are excreted from the body.

Answer 1

kidney(renal), biliary (feces)

Question 2

Identify the processes involved in renal excretion

Answer 2

filtraction, reabsorption, secretion

Question 3

what are the anatomical location s of the processes involved in renal excretion

Answer 3

filtration
- glomerulus
secretion
- proximal convoluted tubule
reabsorption
- distal convoluted tubule
biotransformation
- kidney and liver (vitamin D)

Question 4

what are the mechanisms of hepatic elimination

Answer 4

metabolism and biliary excretion

Question 5

Plot the relationship between MW and renal clearance.

Answer 5

increase in renal clearance with inc in MW

Question 6

Plot the relationship between dose and urinary excretion rate for a drug that undergoes filtration only and one eliminated primarily through renal excretion.

Answer 6

• With filtration only the excretion rate is an increase
  –> Increase in CLR with inc. in creatinine clearance
• With active tubular secretion it increases but then reaches a saturation point due to being a carrier-mediated process

Question 7

Plot the relationship between MW and percent excreted in the bile.

Answer 7

As MW inc. Bile inc.

Question 8

Describe the impact of enterohepatic recirculation on drug half-life in the body.

Answer 8

• EHR will increase the half-life because of it getting reabsorbed and continuing the process of reabsorption from the intestine
• If used with some bile binding agent the half-life will decrease because it is not reabsorbed

Question 9

what is the first-pass effect of pre systemic circulation

Answer 9

all blood from stomach and small intestine flow to the portal veinal absorbed drug passes through the liver before entering the rest of the body. if drug is metabolized or excreted in bile unchanged, a significant fraction of the dose may be eliminated before entering the systemic circulation

Question 10

what is the passage of drug from the blood to the liver

Answer 10

• from hepatic vein or artery from sinusoid
• out to in
• active transport

Question 11

why are transporter proteins important

Answer 11

uptake and efflux from the blood and transport to bile

Question 12

how does bile move

Answer 12

in to out

Question 13

where does bile get collected

Answer 13

hepatic duct (canaliculi)

Question 14

what is the passage from the liver to the intestine

Answer 14

1. bile moves via hepatic duct to gall blader
2. bile stored and concentrated in gall bladder
3. bile released in intervals from gall bladder into intestine

Question 15

what are the classes of agents

Answer 15

a,b,c

Question 16

what is the enterohepatic cycles

Answer 16

small intestine –> portal vein –> liver –> bile duct
–> repeat

Question 17

what is pulmonary excretion

Answer 17

any volatile compound that has potential for pulmonary excretion
- simple passive diffusion

Question 18

what are other routes of excretion

Answer 18

hair, sweat and saliva, milk, tears

Question 19

what is the optimal MW for biliary excretion

Answer 19

> 300-400
- optimal 500-600