3 - drug interactions

Question 1

what are two ways that drugs can interact

Answer 1

influence effectiveness by altering its availability (kinetics) or altering its interactions with its receptor (dynamic)

Question 2

what is pharmacodynamics

Answer 2

What drug does to body

Question 3

what is pharmacokinetics

Answer 3

what body does to drug

Question 4

what is the pharmacokinetics consideration of drug interactions

Answer 4

how one drug may influence the effectiveness of another drug

Question 5

what is the pharmacodynamic consideration of drug interactions

Answer 5

how one drug alters another drug’s interaction with its receptor

Question 6

how does theraputic index relate to drug interactions

Answer 6

drugs with narrow theraputic index are most susceptible to issues with drug interactoins

Question 7

what can result from a small change in availability of a drug

Answer 7

significant changes too outcome (too much causing toxic, too little so no therapy)

Question 8

what is an antagonist interaction

Answer 8

drug A acts as an antagonist at receptor for drug B

Question 9

is antagonist interaction a pharmacodynamic or pharmacokinetics

Answer 9

pharmacodynamic (drug does to body)

Question 10

what is an example of an antagonist interaction?

Answer 10

vitamin K rich foods on warfarin

Question 11

what is warfarin

Answer 11

anti-coagulant in patients with blood clot issues

Question 12

how does warfarin work

Answer 12

inhibitor of Vit K epoxide reductase

this causes a reduction of clotting factors (red. VitK is used to make prothrombin)

Question 13

what does VitK epoxide reductase do

Answer 13

recycle oxidized Vit K into reduced Vit K

Question 14

what is a role of reduced vitamin K

Answer 14

helps make prothrombin

Question 15

what is prothrombin time

Answer 15

measure of time required for blood to clot under a set of standard lab conditions

Question 16

what is international normalized ratio

Answer 16

the ratio of the clotting time compared to a normal sample

Question 17

what does a high what is international normalized ratio

Answer 17

sample requires a long time to clot

Question 18

what does a low what is international normalized ratio

Answer 18

sample requires a short time to clot

Question 19

what is the ideal international normalized ratio

Answer 19

2-3

Question 20

what does vitamin K do to the effectiveness of warfarin

Answer 20

reduces it

Question 21

how does vitamin K affect the effectiveness of warfarin

Answer 21

it is a competitive inhibitor for the enzyme (vit K epoxide reductase)

Question 22

what happens to the effectiveness of warfarin if VItK is diminished

Answer 22

stronger effectiveness

Question 23

what are synergism/additive interactions

Answer 23

multiple agonists/modulators that act on the same receptor leading to excessive activation

Question 24

is additive/synergism interaction a pharmacodynamic or pharmacokinetics

Answer 24

pharmacodynamic (drug does to body)

Question 25

what does synergism mean

Answer 25

effects that are greater than the inividual effects of the two drugs

Question 26

what does additive mean

Answer 26

effects that are roughly the sum of the individual effects of two drugs

Question 27

what is an example of excessive receptor activation (synergism additive)

Answer 27

bezos, alcohol, barbiturates and other GABA A receptor modulators

Question 28

what is the mechanism of action of benzodiazepines

Answer 28

positive allosteric modulators of GABA A

Question 29

what is the mechanism of action of barbiturates

Answer 29

positive allosteric modulators or agonists of GABA A

Question 30

what is the mechanism of action of alcohol

Answer 30

positive allosteric modulators of GABA A

Question 31

what is the mechanism of action of zolpidem

Answer 31

positive allosteric modulators of GABA A

Question 32

is indirect interaction a pharmacodynamic or pharmacokinetics

Answer 32

pharmacodynamic

Question 33

what is indirect interaction

Answer 33

the effects of multiple drugs might influence the same signalling pathway, but not necessarily the same receptor

Question 34

what is an example of an indirect interaction

Answer 34

serotonin syndrome

Question 35

what is serotonin syndrome ( cause+effect)

Answer 35

arise from a combination of drugs that lead to an over abundanceof 5HT in the CNS and overstimulation of 5HT receptors (especially 5-HT2A and 1A)

Question 36

how do MAOIs contribute to serotonin syndrome

Answer 36

inhibit breakdown of 5HT | lots of them act irreversibly

Question 37

how do TCAs contribute to serotonin syndrome

Answer 37

prevent reuptake of 5HT from synaptic cleft

Question 38

how do SSRI contribute to serotonin syndrome

Answer 38

prevent reuptake of 5HT from synaptic cleft

Question 39

how do SNRI contribute to serotonin syndrome

Answer 39

prevent reuptake of 5HT from synaptic cleft

Question 40

how do some opioids contribute to serotonin syndrome

Answer 40

metabolites may have direct serotonergic effects or interfere with serotonin reuptake

Question 41

how do St. John's wort contribute to serotonin syndrome

Answer 41

serotonin reuptake inhibitor

Question 42

how do MDMA and methamphetamine contribute to serotonin syndrome

Answer 42

use efflux pumps (transport in reverse)

Question 43

what are 2 ways of how can you alter drug availability pharmacokinetically

Answer 43

drugs that alter gut motility that affect absorption | drugs that alter local blood flow can alter absorption (lidocaine+epinephrine)

Question 44

how is lidocaine+epinephrine an example of pharmacokinetic drug interaction way to alter drug availability

Answer 44

alters absorption because the epinephrine vasoconstricts so that lidocaine can stay in the area

Question 45

what are two ways that CYP can be affected by food or drugs

Answer 45

induce expression of specific CYP enzymes (reduce lifetime and abundance of their substrates) inhibit CYP activity (prolong lifetime and abundance of the substrates)

Question 46

what is the role of biotransformation

Answer 46

metabolism in the liver

Question 47

what is phase 1 biotransformation

Answer 47

oxidation via CYP

Question 48

what is phase 2 biotransformation

Answer 48

conjunction with large polar additions

Question 49

which enzymes metabolizes warfarin

Answer 49

CYP3A4

Question 50

which is the most common CYP enzyme

Answer 50

CYP3A4

Question 51

which food inhibits CYP3A4

Answer 51

grapefruit juice

Question 52

what happens to someone who has a lot of grapefruit who also takes warfarin

Answer 52

heightened sensitivity to warfarin or other drugs metabolized by CYP3A4

Question 53

what does grapefruit juice do to CYP3A4

Answer 53

inhibit it

Question 54

check online diagram he said hed post

Answer 54

make more questions

Question 55

what are product monographs

Answer 55

where the drug interactions are listed

Question 56

what is INR

Answer 56

the ratio of clotting time compared to a control

Question 57

what does high INR mean

Answer 57

the samples takes a long time to clot

Question 58

what does low INR mean?

Answer 58

sample doesn't take long to clot

Question 59

how is prothrombin time measured

Answer 59

in INR (international normalized ratio)