Intraveneous Bolus Administration PK

Question 1

Characteristics of Intravenous Bolus Administration

Answer 1

Intravenous administration ensures that the entire dose reaches general circulation.

The desired concentration in of the drug is quickly achieved.

Doses must be carefully calculated to avoid toxic or undesired effects.
One compartment model is assumed.

First order kinetics are observed and passive diffusion is assumed.

No metabolism occurs – 100% excreted via renal excretion.

Drug can be monitored in plasma and urine

Question 2

The rate of decrease of amt of drug in compartment is controlled by

Answer 2

rate constant k.

Question 3

study of the relationships between drug dosage regimens and concentration–time profiles

Answer 3

Pharmacokinetics

Question 4

three fundamental parameters that control these relationships are

Answer 4

1. Elimination half-life (t1/2): Half-life can be used to calculate the optimal dosage interval to produce the target peak-to trough difference.
   
   2. Volume of distribution: Knowledge of distribution volume can be used to calculate a loading dose so as to achieve a target concentration quickly.
   3. Clearance (CL): CL can be used to calculate the dose rate required to maintain a target concentration.

Question 5

Apparent Volume of Distribution

Answer 5

NOT a physical volume
proportionality constant between plasma concentration and dose.
can sometimes exceed the volume of the human body (~70L)

Question 6

if the dose amount is 200 mg, and drug concentration was found 0.2mg/mL, what is the Vd?

Answer 6

1000 mL

Question 7

if the dose amount is same i.e., 200 mg, and drug concentration was found 0.1 mg/mL, what is the Vd? What does it mean?

Answer 7

2000 mL, drug is more distributed to other organs/tissue

Question 8

Is it possible to get higher Vd than the total body volume?

Answer 8

yes

Question 9

If a drug is protein-bound drug, the Vd will be
A. High
B. Low

Answer 9

low

Question 10

Is the volume of distribution of these drugs high or low and why
Heparin
warfarin
ethanol
chloroquine

Answer 10

heparin=lowest=distributed in only blood
warfarin= low= plasma bound
ethanol= high= distributed in total body volume
chloroquine= highest= distributed in body fat