lecture one Flashcards
pharmodynamics
what the drug does to body
toxicodynamics
what toxicant does to body
it is the does that changes…?
the dynamics from pharmacodynamics to toxicodynamics
antidotes?
glucose for diabetes
naloxone for opiods
succimer for lead poisioning
why is absorption important?
helps predict onset and extent of action
what alters rate and extent of absorption?
formulation of product (liquid vs solid)
bioavailability
1st pass effect
what slows down or decreases GI absorption?
anticolinergic agents hypotension pharmacobezoar/glob of pills aggregation into a mass - decreases surface area and disintegrates slowly may have multiple peaks
pharmaco/toxicokinetics can predict
onset of efficacy/toxicity
duration of efficacy/toxicity
bioavailability
% or fraction of an administered dose that reaches systemic circulation
example: IV= 100% bioavailable
1st pass effect?
large percent of drug is extracted prior to leaving the liver during the 1st pass through it
enterohepatic recirculation
can lead to prolong toxicity bc drug is circulated around body more than once
why is distribution important?
bc needs to reach site of action to cause effect
what alters distribution?
protein binding molecular size lipid solubility time ionization status
Redistribution
drug redistributed back to the plasma from wherever it was hiding in the body. can cause drug level to become high again
volume of distribution formula
lower plasma level of dose = higher distribution
and vice versa
protein binding
free drug is active and bound drug is inactive
dialysis does what?
clears the free drug which causes the toxicity
protein binding a significant weight loss?
serum very low which caused higher range of free drug
ionized drug is excreted how?
through urine
how does 1/2 life relate to duration of toxicity?
faster 1/2 life = faster body clears it
p450 system
responsible for drug metabolism
idiosyncratic
side effect or toxic effect not related to the serum level but related to just the toxin
example: one bee sting may not kill a person but someone who is allergic to bee sting can be killed by just that one sting
arsenic chelators
BAL
DMSA (Succimer)
