toxicology exam 1 Flashcards
factors that increase toxicity
co-morbidities
loss of protective mechanisms
co-exposures
genetics
most common route of occupational exposure
inhalation
most common route of poison exposure
ingestion
routes of exposure to toxins
inhalation ingestion dermal absorption wounds occular
effects of acute toxicity
cellular/organ dysfunction receptor interactions cell death interference with vital processes inflammation
effects of chronic toxicity
cumulative dysfuntion chronic inflammation cell proliferation dysfunctional repair mechanisms fibrosis
polypharmacy
multiple drugs prescribed
common problem for elderly
risk factors for drug interactions
age
multiple prescribers
inadequate monitoring
impaired drug elimination (liver/renal disease)
drugs with narrow therapeutic index (coumadin)
impaired elimination
when taking 2 drugs, one can impair the elimination or metabolism of the other, making it more likely to reach a toxic threshold
slow vs fast metabolizers
slow metabolizers more likely to get to a toxic level of a drug, fast metabolizers less likely to get to a therapeutic level
6 mechanisms of toxicity
receptor-ligand interactions perturbation of membrane function interference with ATP generation interaction with macromolecules alteration of calcium homeostasis generation of free radicals
what interferes with receptor-ligand interactions
PCBs, bisphenols, estrogen
example of membrane disruption
ETOH, Na channel disruption
what interferes with ATP generation
CN, Hydrogen sulfide
what interferes with macromolecules
CO binds to Fe, metals and sulfhydryl groups, lipid peroxidation
what alters calcium homeostasis
foxglove, digoxin
what happens to ROS/Carbon radicals in times of oxidative stress
Increases: P450 metabolism reperfusion ischemia xenobiotics
what happens to antioxidants in times of oxidative stress
Decreases:
GSH depletion
low SOD fxn
malnutrition
what is an antioxidant
can donate an electron to a free radical
ex. GSH, readily donates a H
what happens with Paraquat exposure
pulmonary fibrosis
lung toxicity
mechanism of paraquat toxicity
yields hydroxyl radical
organophosphate/carbamate insecticide
parathione
inactivates acetyl cholinesterase
inhibits enzyme fxn
organophosphate carbamate antidote
atropine sulfate/ anti-muscarinic
what causes methemoglobin toxicity
exposure to nitrates
makes Hb-Fe+++
