# Pharmacokinetics Calculations Practice Questions With Answers

43 Questions | Total Attempts: 464  Settings  Can you solve this 'Pharmacokinetics calculations practice questions with answers' quiz? If yes, attempt the quiz then. In this scored quiz, we've asked some key pharmacokinetic calculations, and you've to choose the correct answer for each question. Basically, pharmacokinetic, abbreviated as PK, is a branch of pharmacology that deals with drug absorption, distribution, metabolism, and excretion. So, are you ready to take up the test? If yes, all the best, my friend!

• 1.
The concentration of a drug X is 29 mg/ml in hepatic artery, while its concentration in hepatic vein is 6 mg/ml If you know that the flow rate to the liver is 32 L/mm. Accordingly, the hepatic clearance (L/mm) will be equal to
• A.

0.53

• B.

3.5

• C.

2.5

• D.

0.57

• E.

94.4

• 2.
After an intravenous bolus administration of a drug X (6.5 g), it was found that its initial rate of elimination is 120.4 mg h’1. Determine the total clearance (L/hour) of this drug if the apparent volume of distribution is reported to be 23 L
• A.

1

• B.

0.714

• C.

0.43

• D.

1.27

• E.

0.742

• 3.
Regarding kinetic homogeneity, choose the correct statement:
• A.

Drug concentration at the site of action equals the drug concentration in the measured biological fluid (usually blood)

• B.

It is a valid for all drugs

• C.

Drug concentration at the site of action is lower than drug concentration in the measured biological fluid (usually blood)

• D.

None of the options is correct

• E.

Drug concentration at the site of action is at dynamic equilibrium with the drug concentrations measured biological fluid (usually blood)

• 4.
The concentration of a drug X entering the liver is 40 mg/ml while its concentration in hepatic vein is 35 mg/ml If you know that the flow 'ate to the liver is 4 2 L/mm. Accordingly, according to what you know, the hepatic extraction ratio (ER) of drug X will be considered as:
• A.

No extraction is happening in the liver.

• B.

Low

• C.

Complete

• D.

. Intermediate

• E.

High

• 5.
The plasma concentration (Ln transformed) vs time (hours) of a drug that rs following a first-order and one compartment kinetics, knowing that the unit of the measured concentration is mg/l. and the equation of LnCp vs time on a RL graph is (y=-0.782x+6.8) Based on this information answer the following TWO questions (Part 1/2): Based on the information mentioned above, the elimination half-life, in hours, of this drug is:
• A.

1.80

• B.

0.38

• C.

0.89

• D.

0.10

• E.

0.78

• F.

0.78

• 6.
For a drug that is mainly eliminated through the liver. If you know that the hepatic flow rate is 0.2 l/mm and the intrinsic clearance of this drug is 1.9 L/min. Accordingly, in this case the hepatic clearance is mainly limited by
• A.

The hepatic flow rate

• B.

The extent of tissue binding in the liver

• C.

None of the above is correct

• D.

. The number of total organs in the body

• E.

The intrinsic clearance

• 7.
For a drug giving as IV-bolus single dose, and it follows a one-compartment linear kinetics, choose the INCORRECT statement:
• A.

All of the option are correct

• B.

The drug absorption follows first order kinetics

• C.

The drug is mixed instantaneously and homogenously in systemic circulation

• D.

. The drug elimination follows first order kinetics

• E.

The drug in the systemic circulation is in rapid equilibrium with drug in the extravascular tissues/organs

• 8.
If a drug has a half-life of 5 h, how long it takes for a toxic plasma concentration of 20 mg/ml to decline to a therapeutic plasma concentration of 1.25 mg/ml. assuming first-order elimination?
• A.

31.8 h

• B.

37.1 h

• C.

35 h

• D.

42 h

• E.

Information is not enough

• F.

20 h

• 9.
Regarding total AUG of a drug that is given as IV-bolus dose and follows linear pharmacokinetics: Total AUG is AUG from t=0 until t=infinity
• A.

True

• B.

False

• 10.
In linear pharmacokinetics, apparent volume of distribution, usually: Decreases, as the drug is more bound to plasma-proteins
• A.

True

• B.

False

• 11.
Drug x shows zero-order elimination. When an intravenous-bolus dose of 80 mg of drug x was given, it took 48 hours for 30% of the drug initial amount to be eliminated. What is the elimination rate constant (mg/h) of drug x?
• A.

30

• B.

60

• C.

80

• D.

0.5

• E.

1.3

• F.

1.3

• 12.
Just after an IV bolus dose of a drug, the plasma drug concentration was 25.4 mg/ml Seven hours later, the concentration was 10.1 mg/ml. Predict the plasma drug concentration at 9 hours after the dose administration (mg/ml), knowing that the drug follows a first-order and one-compartment kinetics:
• A.

81.93

• B.

9.06

• C.

7.76

• D.

69.29

• E.

25.35

• 13.
A weak base (pka=9) is eliminated by renal excretion. Its excretion includes glomerular filtration, tubular secretion, and tubular reabsorption (passive pathways). Accordingly, answer the following two questions. (Part 1 /2): Which of the following pHs will cause the minimum renal excretion:
• A.

7

• B.

9

• C.

10

• D.

11

• E.

8

• F.

8

• 14.
Choose the CORRECT statement, regarding the renal elimination:
• A.

The tubular reabsorption can never be a site for drug-drug interaction

• B.

The glomerular filtration can be a site for saturation

• C.

The glomerular filtration can be a site for drug-drug interaction

• D.

The glomerular filtration can be measured by the renal clearance of inulin

• E.

The tubular reabsorption can never be saturated

• 15.
If there is a drug, which is given as IV-bolus and follows one-compartment disposition kinetics, and you know that 54% of the dose gets eliminated within 2.4 hours, using the previous information, what is the elimination HALF-LIFE in hours?
• A.

0.324

• B.

3.7

• C.

2.1

• D.

4.9

• E.

0.46

• 16.
Using the previous information, and if I told you that 42% of the drug elimination was caused by metabolism and the apparent volume of distribution of the drug is 39 L Then the renal and metabolic clearances (L/hour) are:
• A.

7.32 and 5.30. respectively

• B.

5.30 and 7.32. respectively

• C.

0.08 and Oil. respectively

• D.

3.22 and 2.33 respectively

• E.

0.11 and 0 08 respectively

• 17.
Using the previous information, the renal excretion rate constant (1/hour) of the drug:
• A.

58

• B.

0.08

• C.

0.14

• D.

0.42

• E.

0.19

• 18.
The flux of drug via linear passive diffusion absorptive transport rate (amount/time), oral drug administration:
• A.

. increases, as diffusivity of the drug in the membrane decreases

• B.

Decreases, as the concentration gradient across the physiological membrane increases

• C.

Decreases, as the surface sectional area of the physiological membrane increases

• D.

Decreases, as the viscosity of the membrane increases

• E.

Increases, as the thickness of the physiological membrane increases

• F.

Increases, as the thickness of the physiological membrane increases

• 19.
A drug was given through intramuscular route and it was found that it follows one-compartment linear disposition kinetics. When the fraction of the unabsorbed bioavailable drug (remained to be absorbed) was plotted vs. time (hours) on a SEMILOG graph, a linear graph resulted and the equation of the linear regression of that line is: y = -0.05 x - 0.0095 Accordingly, the absorption half-life (hours)
• A.

6

• B.

13.7

• C.

7.3

• D.

Information provided is not enough to get the requested time.

• E.

3.2

• 20.
If a drug has a half-life of 7 h, how long it takes for a toxic plasma concentration of 40 mg/ml to decline to a therapeutic plasma concentration of 1.25 mg/ml, assuming first-order elimination?
• A.

35 h

• B.

81 h

• C.

Information is not enough

• D.

25 h

• E.

20 h

• 21.
In pharmacokinetics, when we assume that elimination follows a linear kinetics it means:
• A.

The drug m the systemic circulation s in rapid equilibrium with drug m the Iiver

• B.

None of the options K true

• C.

A constant amount is eliminated in a specific time interval regardless of drug amount in the body

• D.

The drug distribution is imtantanrout

• 22.
If a drug has half-life of 12 h , how long it takes for a toxic plasma concentration of 20 mg/ml to decline the a therapeutic plasma concentration of 0.625 mg/ml assuming first-order elimination
• A.

25

• B.

70

• C.

42

• D.

72

• E.

60

• 23.
Which of the following is (are) TRUE about the apparent volume of distribution assuming am compartment model?
• A.

High binding to tissues proteins increases the orient of drug distribution

• B.

• C.

This volume of distribution is a physical volume

• D.

Larger volume of distribution means mat the drug has low  tendency to leave

• 24.
Just after an IV bolus single dose of a drug, the plasma drug concentration was 14.9 mg/ml Seven hours later, the concentration was 4.1 mg/ml Knowing that the drug follows a first-order and one-compartment kinetics. If the same dose was used predict the plasma drug concentration at four hours after the dose administration (mg/ml);
• A.

51.25

• B.

68.71

• C.

11.0

• D.

5.15

• E.

1.36

• F.

7.13

• 25.
Which of the following is CORRECT regarding clearance?
• A.

Total body clearance can be less than the hepatic metabolic clearance tor any drug

• B.

Total body clearance is dose-dependent under linear pharmacokinetics assumption

• C.

All of the answers are correct

• D.

Renal clearance is the proportionality constant that relates the rate of drug excretion Amount., time' to the drug concentration in plasma under linear PK

• E.

Total body clearance has the units of amount per time per kilogram

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