Lecture 2

Question 1

Which of the following patient scenarios is associated with a smaller Vd

A. Dose= 500 mg and initial serum conc. is 40 mg/L

B. Dose= 20 mg and initial serum conc. is 1.5 mg/L

Question 2

__________: fluid portion + elements ( white cells, red cells, and platelets)

Answer 2

Blood

Question 3

_________: only fluid portion of the blood (including soluble proteins but not elements)

Answer 3

Plasma

Question 4

_________: when the soluble protein of fibrinogen is removed from plasma

Answer 4

Serum

Question 5

Serum refers only to the fluid portion of blood , including soluble proteins but not cellular elements

False!

Question 6

If Cfinal is greater than Cinitial then it is _________an organ

Answer 6

clearing

Question 7

_____________ is a measure of the removal of the drug from body

Answer 7

CL(Clearance)

Question 8

Describes the removal of drug from a volume of plasma in a given unit of time

Answer 8

Clearance

Question 9

Clearance (Cl) = Volume of __________cleared (“cleansed”) of drug, per unit of time (conceptual definition); always in units of volume/time (e.g., L/hr, ml/min)

Answer 9

plasma

Question 10

Clearance Does NOT indicate the amount of drug being removed, but, the VOLUME of plasma from which the drug is completely removed

Question 11

Cl and Vd determine the _______________

Answer 11

half-life

Question 12

Clearance (Cl)

Cl(total body) = Cl(metabolic) + Cl(renal) + Cl( bile) + Cl(other)

Question 13

Drugs removed primarily by kidneys: Clr makes up most of the total body Cl

Question 14

Clearance is independent of the ________

Answer 14

dose

Question 15

EXAMPLE:For drug X, individual organ clearances have been determined as follows:

Renal Cl
180 mL/min
Hepatic CL
22 mL/min
Pulmonary Cl
5.2 mL/min

How would you describe the clearance of drug X?

How much is total body Cl of drug X?

Question 16

Vd and Cl

Plasma drug concentrations are affected by: _______ at which drug is administered, the ___________ in which it distributes, and its CL

Answer 16

rate, volume

Question 17

Clearance is not the ______________

Answer 17

elimination rate

Question 18

Large clearance will result in low ______________

Answer 18

AUC

Question 19

The drug CL of any organ is determined by _______________and the extraction ratio:

Answer 19

blood flow

Question 20

Understanding the Importance of Clearance in Clinical Scenarios

Dosage Recommendations: Clearance is invaluable for formulating ______________ in clinical settings.

Drug Disposition Parameter: It’s the primary metric detailing the ____________ at which drugs are eliminated from the body.

Index of Removal Capacity: Clearance serves as an indicator of the capacity of body organs to remove a drug.

Example: Propranolol: This drug is primarily eliminated by the liver with an efficiency (E) of 0.9. This indicates that a significant portion of the drug presented to the liver is cleared in one pass. Hence, its clearance (Cl) is approximately equal to the liver’s blood flow rate (Q).

Answer 20

dosage suggestions

speed

Question 21

_________________: The quantity (expressed in terms of mass, NOT volume) of the drug removed from the body over a specific time duration.

Measurement: Always in units of mass/time (e.g., mg/min)

Dynamics: As the drug concentration decreases, the elimination rate also drops over time.

Answer 21

elimination rate

Question 22

Clearance:

Relationship with Elimination Rate: Clearance remains constant and is calculated as the ratio between ____________ and _____________.

Independence: Clearance operates independently of the drug quantity present. Consequently, introducing more of the drug will not alter the clearance rate

Answer 22

elimination rate

drug concentration

Question 23

k is the proportionality constant relating the rate of change of drug concentration and the concentration (1st order elimination)

Question 24

k is the first order rate constant describing _________________

Answer 24

drug elimination

Question 25

REMEMBER : elimination rate constant represents the fraction of drug removed over a unit of time. e.g., if k = 0.25 hr-1 then 25% of the drug remaining in the body is removed each hour

Question 26

REMEMBER : In a 1storder elimination process, although the amount of drug eliminated may change with the amount of drug in the body, the fraction of a drug eliminated over a given time remains constant

Question 27

The meaning of 1st order elimination k

The actual amount of drug eliminated is different for each fixed time period depending on the initial amount in the body but, the ____________ removed is the same

Answer 27

fraction

Question 28

Practical term: fraction or percentage of drug being removed is the same either with high or low concentration

Question 29

Question: With a drug that follows 1st order elimination, the amount of drug eliminated per unit time: decreases while the fraction of the drug eliminated remains constant

Question 30

Because the extraction ratio can maximally be 1, the maximum value that hepatic clearance can approach is that of :

Answer 30

Hepatic blood flow