Pharmacokinetics

Question 1

Three ways to cross a cell membrane

Answer 1

channels and pores
transport systems
direct penetration (most common, lipid soluble)

Question 2

Four basic processes of pharmacokinetics

Answer 2

absorption
distribution
metabolism
excretion

Question 3

Which of these can cross cell membranes: lipids, polar molecules, ions

Answer 3

just lipids

Question 4

Movement of drug from its site of administration into the blood

Answer 4

absorption

Question 5

Factors of absorption

Answer 5

rate of dissolution
surface area
blood flow
lipid solubility
pH partitioning

Question 6

enteral

Answer 6

GI tract

Question 7

parenteral

Answer 7

Goes straight into the blood stream: intravenous, subcutaneous, intramuscular

Question 8

Which of these routes are parenteral: subcutaneous, nasogastric tube, transdermal, intravenous

Answer 8

subcutaneous

intravenous

Question 9

sustained release

Answer 9

formulation change to allow for ongoing release – pts can take less frequently

Question 10

movement of drugs throughout the body

Answer 10

distribution

Question 11

components of distribution

Answer 11

blood flow to the tissues
exiting the vascular system
ability of the drug to enter the cell

Question 12

blood brain barrier

Answer 12

protective mechanism for the brain: tight capillaries make it difficult for drugs to penetrate

Question 13

Which drugs can pass most easily to a fetus

Answer 13

lipid-soluble and non-ionized

Question 14

enzymatic alteration of a drug

Answer 14

drug metabolism

Question 15

where does drug metabolism take place (mostly)

Answer 15

liver

Question 16

cytochrome p450

Answer 16

12 closely related enzymatic processes that change the drug

Question 17

Ways CYP can change drug

Answer 17

accelerate excretion
inactivate/activate
↑/↓ toxicity
↑/↓ metabolism (inducers/inhibitors)

Question 18

First Pass Effect

Answer 18

oral meds go from GI tract to liver, inactivating a portion of the drug

(time delay, different dosage parenteral and enteral)

Question 19

removal of drugs from the body

Answer 19

excretion

Question 20

primary organ of drug excretion

Answer 20

kidneys

Question 21

Drug excretion pathways

Answer 21

lungs, milk, sweat/tears/skin/hair, saliva, bile, urine

Question 22

three factors affection drug excretion from kidneys

Answer 22

glomerular filtration rate
passive tubular reabsorption
active tubular secretion

Question 23

lag period

Answer 23

time between drug initiation and onset of effect

Question 24

therapeutic window

Answer 24

range between desired response and adverse response

Question 25

why is half-life important? (3)

Answer 25

It’s a major determinant of:

• duration of action after a single dose
• time required to reach steady state
• dosing frequency

Question 26

t1/2

Answer 26

drug half life

Question 27

how many half lives does it take for the drug to plateau

Answer 27

4 (the amount of drug eliminated between doses equals the amount ingested)

Question 28

how many half lives does it take for most of the drug to be eliminated

Answer 28

4

Question 29

what are loading doses

Answer 29

higher or more frequent dosage at initiation to make plateau faster

Question 30

peak level

Answer 30

greatest concentration of the drug in the blood (30 minutes after infusion)

Question 31

trough level

Answer 31

greatest concentration of the drug in the tissue (30 minutes prior to next infusion)

Question 32

why is trough important

Answer 32

high trough can increase potential for adverse effects – may hold dose

Question 33

efficacy

Answer 33

the largest effect a drug can produce

Question 34

potency

Answer 34

dosage needed to produce effect

Question 35

t/f: selective drugs are safer

Answer 35

false

Question 36

the more selective a drug is, the [more/fewer] side effects it will produce

Answer 36

fewer

Question 37

strength of attraction between drug and receptor

Answer 37

affinity

Question 38

ability to activate receptor upon binding

Answer 38

intrinsic activity

Question 39

agonist drug

Answer 39

affinity and intrinsic activity: mimics and enhances body response and cellular activity

Question 40

antagonist drug

Answer 40

affinity without intrinsic activity: binds to receptor and blocks normal body response