Pharmacokinetics & Pharmacodynamics

Question 1

Pharmacodynamics

Answer 1

therapeutic/ toxic actions of the drugs on the body

Question 2

Pharmacokinetics

Answer 2

Effect of the body on the drug
- mathematically predicts effectiveness and dosage
- predict, monitor, and adjust dosing schedule to optimize efficacy and safety

Question 3

Pharmacogenetics

Answer 3

Effects of genetics on how drug is metabolized by body and how it affects body
- can sequence DNA and predict individual response to drugs

Question 4

Toxicology

Answer 4

Examines undesirable effects of chemicals on body

Question 5

Overall pharmacokinetic process

Answer 5

LADME:

Liberation
Absorption
Distribution
Metabolism
Elimination

Question 6

What 2 factors determine drug availability ?

Answer 6

Absorption and Liberation

Question 7

Rate of drug liberation depends on (3):

Answer 7

1. Formulation (how drug is packed and what it’s made of)
2. Ionization state
3. Environment pH

Question 8

Factors that influence absorption (4):

Answer 8

1. GI factors (food, pH, SA, enzymes, bacteria)
2. Physiochemical drug properties (solubility, charge, size, structure)
3. Transporters
4. Route of administration

Question 9

Which molecules need help getting across lipid bilayers ? Which can freely diffuse ?

Answer 9

• LARGE and CHARGED need help
• small, neutral molecules freely diffuse

Question 10

Is aspirin absorbed in the stomach or intestine ? Why ?

Answer 10

Stomach; it is neutral in acidic environments

Question 11

How do we assess all pharmacokinetic measurements and processes ?

Answer 11

Area Under the Curve (AUC)
- measures 3 areas
- best indicator of total exposure to a dose

Question 12

Bioavailability

Answer 12

• amount of drug that REACHES CIRCULATION
• determined mathematically = drug goes and AUC from plasma concentration AGAINST time

Question 13

First pass metabolism

Answer 13

• intestine and liver metabolism REDUCES BIOAVAILABILITY of an oral drug before it reaches systemic circulation
• historically, toxic substances are processed by body to prevent sickness

Question 14

Calculate Effective dose using bioavailability factor F

Answer 14

F x dose admin (mg)

Question 15

Differentiate bioavailabilty vs availability of drug

Answer 15

Bioavailability: amount of absorption
Availability: rate of absorption

Question 16

Calculate Effective dose using Bioavailability Factor S

Answer 16

S x F x dose admin (mg)

Question 17

Describe drug Distribution

Answer 17

• delivery of drug via circulation
• equilibrating and partitioning of drug into tissues

Question 18

Volume of distribution

Answer 18

• represents how extensively drug can distribute into different tissues in body

V(d) = total dose/ ([drug] x weight)

Weight = kg

Question 19

Large V(d) vs Small V(d)

Answer 19

Large V(d) = extensive distribution of drug to tissues

[tissue] > [plasma]

Small V(d) = little uptake of drug to tissues

[plasma] > [tissue]

Question 20

How is V(d) affected if drug is more water soluble ?

Answer 20

Increased water solubility = increased plasma concentration = decreased V(d)