L39 - Drug Elimination - Excretion 2

Question 1

What is the rate of renal excretion for a drug eliminated by?

Answer 1

• glomerular filtration
• tubular secretion

Question 2

What happens to ClR when rate of renal excretion eliminated by 2 mechs?

Answer 2

Exceeds its rate of filtration
ClR = funbound x ClR + Clsecretion

Question 3

What happens to renal clearance as unbound fraction increases?

Answer 3

The renal clearance increases
- more filtered, more secreted

Question 4

What is active secretion like?

Answer 4

As you double conc of drug in plasma, excretion rate doubles
until the transporters fully saturated

Question 5

What happens when rate of renal excretion for a drug eliminated by glomerular filtration and reabsorbed?

Answer 5

CiR will be less than its rate of filtration
ClR = funbound x Clcr - Clreabsorption

Question 6

What factors determine passive reabsorption?

Answer 6

• gradient established (more diluted, smaller grad, less reabsorption
• MW

Question 7

How can you increase ClR with urine pH?

Answer 7

Decrease reabsorption by ionising drug