module 1 pharmacodynamics and pharmacokinetics Flashcards
lipophilicity
ability to dissolve in fats, oils, lipids, and non-polar solvents
- drug affinity for lipid environment
therapeutic window
efficacy without unacceptable toxicity
ED50
dose where 50% of people have therapeutic effect
TD50
dose where 50% have toxic effect
LD50
dose where 50% die (lethal)
High therapeutic index
wide window
low therapeutic index
small window
Receptors natural state
non-active
- become active when bound with drug or natural agonist
inverse agonist
binds to receptors who have a natural active state and inactive it.
full agonist
elicits maximal response
stabilizes DR*(active)
partial or mixed agonist-antagonist
activates receptor but not with maximal efficacy
stabilized DR and DR*
Antagonists
inhibition of agonist activity
- stabilization of DR; prevention of DR*
competitive antagonist
reversible binding
competes for same active site
noncompetitive antagonist
irreversible binding to active site
or allosteric site
allosteric site
site other than active site
non-receptor antagonist
chemical: binds to agonist and inactivates it
physiologic: mediates opposite response of agonist
competitive antagonist and drug response
Will eventually get to full drug response but it takes longer due to fighting for binding sites.
noncompetitive antagonist and drug response
drug response will not reach 100% d/t antagonist binding to allosteric site
- non-reversible
pharmacokinetics
what body does to the drug
pharmacokinetics 4 topics
absorption
distribution
metabolism
excretion
absorption
from compartment to circulation
metabolism
free drug-> metabolism -> metabolites (active and inactive) -> excretion
free drug can bind to
receptors
tissue reservoirs
proteins
physiochemical properties for drug transfer
size and shape
solubility at absorption site
degree of ionization
relative lipid solubility (ionized vs nonionized)
passive diffusion
small
hydrophobic/ lipophillic
facilitated diffusion
transporter
no ATP required
active transport
transporter
ATP required
endocytosis
engulfment
nonionized molecules
lipid soluble, easily penetrate
ionized molecules
hydrophilic, difficulty penetrating
pKa
pH at which 50% of drug is ionized
pH trapping
determined by pKa and pH gradient across membrane
- weak acid in stomach becomes non-ionized and will cross to plasma
- in plasma becomes ionized and will not cross back.
CNS penetration
small and hydrophobic
active transport
facilitated transport
intrathecal
pharmacodynamics
what drug does to receoptor/body
efficacy
ability of drug-receptor complex to produce intended response
potency
amount of drug needed to produce effect
- strength
potency and efficacy relationship
drug that requires less to produce the same response (potency) has higher efficacy.
- drugs can have same efficacy but different potency
water-soluble: hydro..
hydrophilic
polar, usually ionized: hydro…
hydrophilic
lipophilic: hydro..
hydrophobic
water insoluble: hydro..
hydrophobic
renal excretion: hydro..
hydrophilic
requires transport mechanism to cross membranes: hydro…
hydrophilic
passively diffuses across membranes: hydro..
hydrophobic
Forms H+ bonds: hydro..
hydrophilic
non-polar, unusually not ionized: hydro..
hydrophobic
