LEC 1 Flashcards
what do drugs interact with
receptors
what does pharmacodynamics deal with
interaction bw drug and receptor
what does pharmacokinetics deal with
how body deals w drug
how does body deal with drugs (4)
- absorb
- distribute
- metabolize
- eliminate
what determines how much drug interacts w receptor
pharmacokinetics
TERFENADINE what was drug used to treat
allergy
TERFENADINE what is H1 receptor
histamine receptor
TERFENADINE what happens when terfenadine absorbed
- absorbed by liver
2. metabolized into fexofenadine
TERFENADINE what kind of drug is terfenadine
pro drug
TERFENADINE what kind of drug is fexofenadine
active drug
what are receptors
molecular drug targets
what is pro drug
- compound that is not intrinsically active
- compound that needs to be metabolized to become active
what are 2 ways drug can be altered
- activated
2. inactivated
how does drug activation / inactivation happen
distinct from drugs actions on its target receptors
what is drug activation / inactivation related to
pharmacokinetics
what does it mean if terfenadine unprocessed (2)
- un metabolized
- inactive
what happens when there are significant amounts of unprocessed terfenadine
acts undesired targets
what are 2 possibilities for off-target receptors
- closely related
2. completely un related
what are adverse events
- undesirable drug effects / side effects that vary in severity
what are on target effect
- adverse event related to mechanism of action of drug
what are off target effect
- adverse event unrelated to mechanism of action of drug
what would be on target effect
- adverse event that arises from antagonism of desired target
what would be off target effect
- adverse event that arises from antagonism of undesired target
why do off target effects happen
- extrinsic ==>substances inhibit terfenadine metabolism
- intrinsic ==>mutations in genes encode for ion channels that are susceptible to unprocessed terfenadine
what is the function of CYP34A enzyme
metabolize terfenadine in liver
what can inhibit CYP34A (3)
- antibiotics
- anti fungals
- components of grape fruit juice
what happens when CYP34A inhibited
increase amount of unprocessed terfenadine
what does it mean for ion channels to be more susceptible
small amount of unprocessed terfenadine enough to cause lethal cardiac arrhythmia
what is influence of terfenadine on heart (undesired target)
block ion channels that control electrical activity + heart beat
what does blocking ion channels result in
lethal cardiac arrhythmia
what is solution
administer fexofenadine
what does pharmacogenomics refer to
how genetics affects how we respond to drug
what is drug interaction
one drug adversely affects response to another drug
