DHA Pharmacist Pharmacokinetics and Pharmacodynamics

Question 1

A drug has a volume of distribution (Vd) of 700 L in a 70 kg patient. What does this suggest?

Accepted Answer

The drug is extensively distributed into tissues

Answer

The drug is largely confined to plasma

Answer

The drug has poor oral bioavailability

Answer

The drug undergoes significant first-pass metabolism

Question 2

A drug has a half-life of 8 hours. Approximately how long will it take to reach steady-state plasma concentration with regular dosing?

Accepted Answer

40 hours

Answer

8 hours

Answer

16 hours

Answer

80 hours

Question 3

Which route of administration completely bypasses first-pass hepatic metabolism?

Accepted Answer

Intravenous

Answer

Oral

Answer

Rectal (proximal)

Answer

Sublingual and intravenous only

Question 4

The bioavailability of an oral drug is 25%. If the IV dose producing the desired effect is 20 mg, what oral dose is required to achieve the same effect?

Accepted Answer

80 mg

Answer

5 mg

Answer

20 mg

Answer

40 mg

Question 5

Hepatic clearance of a high-extraction drug (extraction ratio > 0.7) is primarily dependent on:

Accepted Answer

Hepatic blood flow

Answer

Plasma protein binding

Answer

Renal function

Answer

Glomerular filtration rate

Question 6

A drug follows first-order kinetics. Which of the following statements is TRUE?

Accepted Answer

The rate of elimination is proportional to drug concentration

Answer

A constant amount of drug is eliminated per unit time

Answer

Elimination pathways become saturated at therapeutic doses

Answer

Half-life increases as plasma concentration increases

Question 7

Which pharmacokinetic parameter is most useful when calculating a maintenance dose to maintain a target steady-state plasma concentration?

Accepted Answer

Total body clearance (CL)

Answer

Volume of distribution (Vd)

Answer

Half-life (t½)

Answer

Peak plasma concentration (Cmax)