E1 L8: Bioavailability and Clearance 3

Question 1

FA

Answer 1

Fraction of drug absorbed

Question 2

EG

Answer 2

Fraction of drug that is eliminated by intestinal metabolism during single pass; approx zero

Question 3

Bioavailability (F) Equation

Answer 3

F = QH/(QH + fu * CLint)

Question 4

Low EH drug

Answer 4

F = 1
CLH = Fu * CLint

Question 5

High EH drug

Answer 5

F = QH/ (fu *CLint)
CLH =QH

Question 6

Summary: Low EH (<0.3)

Answer 6

F is close to 1
F is not affected by changes in CLint, fu, or QH
CLH is affected by changes in CLint or fu

Question 7

Summary: High EH (>0.7)

Answer 7

F is affected by changes in CLint, fu, or QH
CLH is proportional to QH

Question 8

If a drug is 100% metabolized, then

Answer 8

CL = CLH

Question 9

Q: T/F: Hepatic metabolism can be the major elimination route for a low EH drug (i.e. fe=0; or no renal excretion)

Answer 9

True

Question 10

Q: T/F: After IV administration of drug X at 100 mg dose, you find 100% (i.e. 100mg) of drug X in the urine as metabolites. The fe of drug X is 1

Answer 10

False

Question 11

Assuming 100% oral absorption, co-administration of an enzyme inducer with a low EH drug (drug X) would

Answer 11

Significantly increase CLH of Drug X

Question 12

Assuming 100% oral absorption, co-administration of an enzyme inducer with a high EH drug(Drug Y) would:
A. Significantly increase F of Drug Y
B. Significantly decrease F of Drug Y
C. Significantly increase CLH of drug Y
D. Significantly decrease CLH of Drug Y

Answer 12

B. Significantly Decrease F of drug Y

Question 13

Assuming 100% oral absorption and fe = 0, co-administration of an enzyme inducer with a high EH drug (Drug Y) would:
A. Significantly increase CL of Drug Y
B. Significantly increase CLpo of drug Y
C. Significantly increase F of Drug Y
D. Significantly increase AUCiv of Drug Y

Answer 13

B. Significantly increase CLpo of Drug Y