Pharmacokinetics

Question 1

What does the effect of a drug depend on

Answer 1

the ability of the drug to travel through the body and reach the brain intact

Question 2

What does concentration of a drug at the site of action depend on

Answer 2

1) dose administered
2) rate of accumulation/removal from site of action

Question 3

what is pharmacokinetics

Answer 3

refers to the processes involved in the movement of drugs within biological systems with respect to absorption, distribution, metabolism, excretion

Question 4

what is absorption

Answer 4

refers to getting the drug from where it is administered to the brain

Question 5

what are the factors related to the body that affect absorption

Answer 5

Area of absorptive surface
vascularity
pH
presence of other substances
GI motility
functional integrity of absorptive surface
diseases

Question 6

what are the factors related to drugs that affect absorption

Answer 6

lipid water solubility
molecule size
degree of ionization
physical forms
chemical nature
dosage forms
formulation
concentration

Question 7

what influences how well a drug passes through a membrane

Answer 7

1) concentration
2) lipid solubility

Question 8

what is lipid/water solubility

Answer 8

drugs must be hydrophobic enough to cross lipid membrane and hydrophilic enough to dissolve in plasma

Question 9

what molecules are hydrophobic

Answer 9

lipids, uncharged molecules

Question 10

what molecules are hydrophilic

Answer 10

charged (polar) molecules

Question 11

what is the oil-water partition coefficient

Answer 11

the relative solubility between the two media

Question 12

what does a higher oil-water coefficient mean

Answer 12

molecule is able to pass through the membrane more easily and less easily dissolves in water

Question 13

what does a lower oil water partition mean

Answer 13

molecule is more easily dissolved in water and less easily passes through the membrane

Question 14

what is the relationship between barriers and time of effect

Answer 14

the more barriers a drug has to pass through the longer/slower the route of administration is

Question 15

what is the slowest route of administration

Answer 15

oral

Question 16

what is the fastest route of administration

Answer 16

inhalation/ intravenous

Question 17

what is intramuscular administration

Answer 17

into a muscle

Question 18

what is subcutaneous administration

Answer 18

under the skin

Question 19

what is intranasal administration

Answer 19

applied to the mucous membranes of the nose

Question 20

what is sublingual administration

Answer 20

under the tongue

Question 21

what is transdermal administration

Answer 21

applied to the skin

Question 22

what is intravenous administration

Answer 22

into a vein

Question 23

why is oral administration the slowest

Answer 23

the drug must pass through the stomach enzymes/acid and the liver

Question 24

what is the first pass effect

Answer 24

applies only to drugs taken orally
blood supply to GI tract goes directly to liver then the rest of the body

Question 25

what factors affect the first pass effect

Answer 25

rate of movement of contents through GI tract
empty stomach
more acidic environment

Question 26

why is intravenous injection fast

Answer 26

drug passes directly into the blood stream bypassing all the barriers

Question 27

why are some drugs that are ineffective when taken orally effective intravenously

Answer 27

there is a faster onset and higher concentration of the drug into the bloodstream

Question 28

what are the disadvantages of IV administration

Answer 28

1) drug has to be soluble
2) weakens veins
3) can get a blood clot formation
4) dangerous (aids, hiv, bacteria)
5) hard to stop overdose if induced with IV

Question 29

what is the seconded fastest method of administration

Answer 29

intramuscular injection

Question 30

what is the third fastest method of administration

Answer 30

subcutaneous, sublingual, intranasal

Question 31

why is inhalation administration effective

Answer 31

lungs have a large surface area and are in close proximity of blood vessels

Question 32

what is the blood brain barrier

Answer 32

regulates passages of substances from the blood stream to the brain

Question 33

how can a drug pass through the blood brain barrier

Answer 33

1) tiny
2) active transport system
3) lipid soluble

Question 34

why should we care about routes of administration

Answer 34

the faster the absorption, the more intense the high
the more intense the high, the more likely you are to get addicted

Question 35

how does metabolism affect a drug

Answer 35

metabolism may make a drug less active (first pass), more active, or have no effect on drug activity

Question 36

what is plasma half life

Answer 36

amount of time it takes to eliminate half of the drug from the blood stream

Question 37

how are most drugs removed from the body

Answer 37

excreted from the kidneys

Question 38

when are the kidneys most effective

Answer 38

when the concentration of the drug is high

Question 39

why is excretion of psychoactive drugs slow

Answer 39

they are very lipid soluble

Question 40

how can excretion of acidic drugs be increased

Answer 40

by making the urine more basic

Question 41

how can the excretion of basic drugs be increased

Answer 41

making the urine more acidic