Pharmacokinetics

Question 1

Pharmacokinetics

Answer 1

a quantitative approach to describe behavior of a drug in the body (what does the body to to the drug)

Question 2

Pharmacodynamics

Answer 2

impact of drugs in the body (what does the drug do to the body)

Question 3

Absorption

Answer 3

movement of drug from site of admin. to bloodstream

Question 4

Very small drugs pass how?

Answer 4

Channels or pores

Question 5

Selective molecule carriers like transport proteins pass how?

Answer 5

Transport system

Question 6

Lipid soluble drugs pass how?

Answer 6

Direct penetration across the cell membrane (most common)

Question 7

Percentage of drug that is in each form at a given time depends on?

Answer 7

pH of the surrounding medium

Question 8

Acidic drugs ionize in?

Answer 8

basic(alkaline) media

Question 9

Basic drugs ionize in?

Answer 9

acidic media

Question 10

Bioavailability

Answer 10

% of drug available in bloodstream after administration compared to IV route

Question 11

IV route bioavailability?

Answer 11

100%

Question 12

Factors that affect oral absorption?

Answer 12

bowel resections, diarrhea/constipation, stomach acidity, food, lipid solubility, rate of dissolution

Question 13

Factors that affect topical absorption?

Answer 13

infant skin, broken or rashy skin, and heat make skin more absorbent

Question 14

Other factors that affect absorption?

Answer 14

greater blood flow at absorption site= faster absorption

Question 15

Drug distribution

Answer 15

movement of drug into body fluids and tissues

Question 16

Volume of Distribution (Vd)

Answer 16

math concept describing amount of drug in body in relation to concentration of drug in blood

Question 17

Loading dose

Answer 17

give extra drug up front to get things going, drug has large Vd

Question 18

6 places drugs get distributed in the body

Answer 18

Blood brain barrier (lipid soluble), placental barrier (lipid soluble), breast milk, blood proteins (albumin), fluid areas, lipid/adipose tissue

Question 19

Drugs bound to plasma proteins are pharmacologically _______ while bound

Answer 19

inactive

Question 20

Binding is ______ and ________

Answer 20

reversible and not permanent

Question 21

Protein binding

Answer 21

some drugs are bound to plasma proteins, mostly albumin

Question 22

Variables affecting Vd and Distribution - infants

Answer 22

body composition of infants are > % of water with < % muscle

Question 23

Variables affecting Vd and Distribution - obese pt’s

Answer 23

larger than expected volume of distribution for drugs that are highly distributed into adipose tissue

Question 24

Variables affecting Vd and Distribution - cachetic (frail) pt’s

Answer 24

have less serum proteins available for binding, neonates and elders have more permeable blood brain barriers

Question 25

Metabolism is?

Answer 25

chemical alteration of the parent compound, resulting in enhanced excretion, inactivation, or active metabolites

Question 26

Where does metabolism occur?

Answer 26

mainly liver (can also occur in GI tract, lungs, blood, kidneys, nerve terminals)

Question 27

Prodrug

Answer 27

inactive compound that must be metabolized to become active

Question 28

Inactive metabolite

Answer 28

de-activated molecule, not pharmacologically active

Question 29

Active metabolite

Answer 29

active molecule but is different than the parent drug; does not have pharmocologically active properties

Question 30

First pass metabolism

Answer 30

drugs absorbed in sm. intestine are first exposed to liver and may be metabolized before becoming systemic

Question 31

First pass metabolism can greatly ______ oral _______

Answer 31

lower; bioavailability

Question 32

Process by which the drug is eliminated from the body

Answer 32

excretion

Question 33

Where are most drugs excreted from?

Answer 33

kidneys (can also occur in bile, intestine, lungs, skin)

Question 34

Drug Clearance is?

Answer 34

volume of blood that is completely cleared of a drug per unit of time

Question 35

How are drugs cleared?

Answer 35

Some through metabolism, some through excretion, and most are through both

Question 36

What is the time required for the drug’s plasma concentration to be reduced by half?

Answer 36

half-life (t 1/2)

Question 37

How many half lives to be cleared from body?

Answer 37

4-5; usually 5

Question 38

Linear Kinetics

Answer 38

as the dose is increased the level in the blood goes up, half life does not change

Question 39

Michaelis-Menten Kinetics

Answer 39

non-linear kinetics

Question 40

Variables that affect clearance (metabolism/excretion)

Answer 40

Age, gender, interacting medications, ethnicity/genetics/heredity, health