Principles of toxicology Flashcards
Teratogenesis is the
creation of birth defects
A teratogen is a
substance that can induce birth defects
The teratogenic effect of any substance depends on
the developmental timing of the exposure
What are the four manifestations of deviant development
Functional deficit
growth retardation
malformation
Death
What period of organogenesis is teratogens most potent
b/t 3rd & 8th weeks of gestation
What is the most common preventable cause of mental retardation
fetal alcohol syndrome
What is the best way to prevent further absorption of a toxic compound
eliminate exposure
Ipecac syrup works by
irritating G.I tracts
activating CTZ
Apomorphine is a
dopamine agonist that works directly on CTZ
Inhibiton of toxication involves
inhibiting the enzymes involved in metabolizing xenobiotics into its toxic product
Name two competetive inhibitors of alchohol dehydrogenase
ethanol
fomepizole
*alcohol dehydrogenase is the enzyme involved in converting alchohol into toxic aldehydes
Enhancement of metabolism is used to tx toxicity by
accelerating metabolism of a toxic substance by inducing the appropriate p450 system
Name an example of enhancement of metabolism
cyanide poisoning and treatment with amyl nitrite, sodium nitrite, and sodium thiosulfate
Name five heavy metal chelators
edatate disodium dimercaprol succimer deferoxamine penicillamine/trientine
edetate disodium tx what metal poisoning
lead
- L.E.D
deFEroxamine tx what metal poisoning
iron
peniCillamine/trientine tx what metal poisoning
copper
Antivenins are
antibodies aganist venoms
One danger with using antibodies as inctivators include
serum sickness
*typer III hypersenstivity rxn
Define xenobiotics
principles of toxicology as they pertain to the behavior of foreign substances
Xenobiotics are modified by phase I/phase II rxn, what are three possible changes
detoxification-rendered less toxic
toxic xenobiotic»converted to another toxic
toxication»harmless xenobiotic»toxic
What are the four mechanisms of toxicity
Large molecular damage (protein, lipid,carbs)
Reactive species (ROS)
Inflammatory and immune mediated
Enzyme and receptor mediated
What is apoptosis
failure of cellular repair mechanism resulting in shrinkage, nuclear condensation and formation of apoptic bodies
*just individual cell affected
What is necrosis
enzymatic digestion of cellular contents, denaturation of cellular proteins and disruption of cellular membrane»inflammatory attracting cells»nearby damage to healthy cells
Following cellular damage, a target organ system can respond in three ways
regenerate
not regenerate
form cancer cells
Name three genes involved in carcinogenesis
proto-oncogens
tumor suppressor genes
tumor promoters
List 4 toxicokinetic-based treatments to minimize patient harm
Prevention of absorption (ipecac syrup)
Inhibition of toxication (ethanlol)
Enhancement of metabolism (Mucomyst)
Enhancement of elimiation (hemodialysis)
List two types of poison inactivators
Heavy metal chelators
antivenins
There are four pharmacologic treatment of toxin ingestion. List and describe them
Pharm Antagonism—-Naloxone
Pharm enhancement of body fx—-physostigmine
Active Site Restoration—methylene blue for methemoglobinemia
Metabolic pathway alternatives—-vitamin K tx for warfarin poisioning
