Lecture 2 part 2

Question 1

__________:Represents the volume in which a drug appears to be evenly distributed when it reaches
equilibrium.

Answer 1

Volume of distribution (Vd)

Question 2

Vd It is NOT a physical or physiological volume.

Instead, it mirrors the space the drug seems to occupy within the body

Question 3

Volume of distribution

Function:
Acts as the proportionality term between the drug’s mass and its concentration.

Interpretation:
Imagine the volume of water required to achieve the same drug concentration as observed in the
blood.

Question 4

Key Role of Vd

Vd indicates the extent of drug distribution into body fluids.

It does NOT specify the exact tissue or fluid where the drug is found.

Question 5

Interpreting Vd Values:

__________Vd: Suggests the drug distributes extensively throughout
the body.

Answer 5

Large

Question 6

_________Vd: Implies that the drug’s distribution into tissues is limited.

Answer 6

Small

Question 7

Variability in Distribution:

Two drugs might share the same Vd value, but their distribution patterns can differ. For instance, one drug might predominantly distribute into muscles, while another concentrates in adipose tissue

Question 8

Volume of Distribution

Although Vd values sometimes correspond to real physiological volumes, many observed Vd values are clearly not equivalent to real physical volumes

Question 9

When Vd is much greater than the subject physical volume this implies sequestration of drug via binding to tissue proteins or concentration in fat

Question 10

Typical Vd Values: Most drugs possess a Vd that’s less than or equal to body mass.

Question 11

Impact of Drug Binding
Binding to peripheral tissues or plasma proteins significantly influences _______.

____________Binding: Leads to a higher initial
concentration (Co) and, consequently, a smaller Vd.

Answer 11

Vd

High Plasma protein binding

Question 12

_____________ Binding: Results in a lower initial concentration (Co) and a larger Vd in turn.

Answer 12

High peripheral tissue binding

Question 13

Vd Beyond Body Mass:
Some drugs might exhibit a Vd that exceeds body mass by multiple times.

Question 14

Distribution Patterns

Drugs with a substantial apparent Vd tend to be more concentrated in extravascular tissues and less so within the vascular region

Question 15

Dosing Regimens:
Vd is a crucial parameter when establishing correct dosing regimens

Question 16

Insight into Drug Location
Vd offers insights into the relative quantities of a drug in both vascular and extravascular tissues.

Question 17

Physiological Significance
While Vd doesn’t correspond directly to a specific
physiological meaning, it’s essential in determining
dosage requirements

Question 18

Dose Proportionality

Typically, dosing corresponds to Vd. A larger Vd suggests that a more substantial dose is needed to attain the desired concentration.

Question 19

Foundation Knowledge

To truly grasp drug distribution, one must first understand the basics of body fluids and tissues.

Question 20

Major fluid distribution in an adult

Intracellular water–> _________

Answer 20

27 Liters

Question 21

Plasma is ____

Interstitial water is 12 liters

Answer 21

3 liters

Question 22

Extracellular water is ________liters

Answer 22

15

Question 23

Totaly body weight is ______liters

Answer 23

40

Question 24

For the body fluid compartment s below, rank
them from the lowest volume to the highest, in a
typical 70-kg person.

A. Plasma < ECF <ICF < total body water
B. ECF < ICF <plasma < total body water
C. ICF < ECF <plasma <total body water
D. Total body water < plasma < ICF < ECF