PHA 5127

First Exam 2004

True or False

For a high extraction drug

1. Hepatic clearance will be larger than that of a low extraction drug

2. Hepatic clearance will depend on liver blood flow

3. Hepatic clearance will depend on plasma protein binding

4. Oral bioavailability will be low

5. Hepatic clearance will be determined by the GFR

 

Compare the following two concentration time profiles after a single bolus injection.. The two lines differ in only one of the subsequent parameters. Please identify which parameter is different.

6. The two lines differ in:

  Parameter
Dose
Vd
Clearance

Matching

For the physiological changes listed below, select the induced changes on the pharmacokinetic parameters for a lipophilic,unionizable (no acid or basic group in the molecule), protein bound high extraction drug that is also eliminated by renal elimination (only filtration, no reabsorption).

Select the effect on kinetics

(A) ClREN decreases

(B) ClHEP increases

(C) oral bioavailability decreases

(D) VD increases

(E) None of the above

Physiological change

7. Increase in metabolic enzymes

8. Decrease in plasma protein binding

9. Increase in liver blood flow

10. Decrease in creatinine clearance

Question Set IV

(Assume GFR is 130 mL min-1 , urine flow is 1.5 mL min-1 ). For the following situations, indicate whether the drug is:

11. A drug with fu =0.04 and a ClREN = 40 mL min-1 is:
12. A drug with fu =0.20 and a ClREN = 26 mL min-1 is:
13. A drug with fu =0.30 and a ClREN = .45 mL min-1 is:
14. A drug with fu =1.0 and a ClREN = .15 mL min-1 is:

Question Set V

A drug is eliminated through glomerular filtration (no other clearance mechanism is observed). It does not bind to plasma proteins. Glomerular filtration rate is normal (130 ml/min). No active renal secretion and passive or active reabsorption after renal filtration is observed. The volume of distribution is 50L.

15. What is the clearance?

(A) 1.3 L/h

(B) 2.2 L/h

(C) 7.8 L/h

(80 L/h

16. What is the ke of the drug?

(A) 0.044 h-1

(B) 0.0260 h-1

(C) 0.1560 h-1

(D) 1.600 h-1

(E) 0.390 h-1

 

Question Set VI

 

17. The nurses gave an iv bolus injection of an unknown drug at 7 am. They also did not record the dose. One hour after injection (8 am) the concentration was found to be 6 mg/L of plasma. Assume a ke of 0.150 h-1 .

What would be the concentration at 8pm?

(A) 1.15 mg/L

(B) 0.8 mg/L

(C) 1.0 mg/L

(D) 0.1 mg/L

(E) 0.2 mg/L

 

Question Set VII

The same dose of triazolam was given either alone or with rifampin. Explain what is going on.

Please chose the correct answer(s).

  1. The clearance of triazolam is decreased in the presence of rifampin
  2. Triazolam is likely to be a high extraction drug
  3. Rifampin is an enzyme inducer
  4. Rifampin increases the volume of distribution of Triazolam.

Question Set VIII

For a lipophilic unionized drug (no acid or base):

19. The renal clearance will depend on the tissue binding of the drug.

20. no question skipped

21. The renal clearance will depend on plasma protein binding.

22. Drinking a lot of water will increase the renal clearance.

23. Involvement of renal transporters in the renal elimination of the drug is likely.

24. The renal clearance will be smaller than the GFR.

Question Set IX

25. The tissue uptake of a lipoh\philic unionized drug is more likely to be perfusion controlled.

26. The degree of plasma protein binding affects the mtabolic clearance of all drugs that are metabolized in the liver.

27. Increase in plasma protein binding will decrease the volume of distribution of a lipophilic drug.

28. The renal clearance of a highly ionized drug is more likely to be affected by drug/drug interactions.

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