Toxicology Pharm Flashcards
bioaccumulation
increasing conc of a substance in the environment resulting from environmental persistence and physical properties (chemically stable, resistant to metabolism and lipid soluble) leading to accumulation in biological tissues
biomagnification
fold increase in concentration of a substance that occurs in a food chain as a consequence of bioaccumulation
tx for CO poisoning
100% oxygen and hyperbaric oxygen
benzene and toluene
acute exposure –> CNS depression w/ ataxia and coma
chronic exposure –> neuro and bone marrow toxicity, leukemia
inhalation –> chemical pneumonitis
why is the root of exposure important in gasoline poisoning?
in ingestion, care must be taken to avoid inducing vomiting
aspiration w/ vomitus can cause fatal chemical pneumonia
LD is much lower in the lung that in GIT
toxic effects of chlorinated hydrocarbons (DTT, DDD, dioxin)
chlorine confers environmental stability
moderately toxic, bioaccumulation, leads to endocrine disruption
no specific tx
toxic effects of carbamates and organophosphates
carbaryl, malathion, parathion
less stable than chlorinated pesticides
muscarinic and nicotinic activators –> SLUDGE sx
tx: atropine blocks receptor activation + pralidoxine to regenerate cholinesterase
lead poisoning toxic effects
acute poisoning –> abdominal colic and CNS changes
chronic poisoning –> peripheral neuropathy, anorexia, anemia, tremor, GI symptoms
+ children growth delays, neurocog defects, developmental delay
lead-line on gums in 50-70%, basophilic stippling of RBCs
what tx prefered to tx lead toxicity in children?
oral succimer
arsenic poisoning sx
acute: severe GI discomfort, rice water stools, vomiting, capillary damage w/ dehydration and shock (like typhoid and cholera)
chronic: skin damage, hair loss, bone marrow depression, anemia, nausea and GI disturbances
causes of arsenic poisoning
usually from environmental water (wells)
Mee’s lines
transverse white lines across the nail from ARSENIC poisoning
mercury toxicity
acute: chest pain, SOB, nausea, vomiting, kidney damage, gastroenteritis, CNS damage
chronic: sore gums and teeth, GI disturbance, neurological and behavioral changes (mad hatter)
fetal toxic
common cause of mercury toxicity
used as an anti fungal agent and can bioaccumulate
iron toxicity sx
vomiting, GI bleeding, lethargy, grey cyanosis –> severe GI necrosis, pneumonitis, jaundice, seizure, comas
tx for iron toxicity
CHARCOAL DOES NOT BIND IRON
use gastric lavage w/in 60 min, whole bowel irrigation w/ polyethylene glycol bowel prep if longer than 60 min
chelating agent: deferoxamine
how do chelators work
for a “chemical cage” to sequester metal ions
have 2 or more electronegative grows that complex cations (bidentate or polydentate)
don’t reverse damage, only prevent further damage
treating poisoned patients - basics
ABCDs: Airway Breathing Circulation Dextrose: for pts w/ altered mental status
tx for acetaminophen tox
activated charcoal w/in 1-2 hrs if possible
N-acetylcysteine w/in 8-10 hrs
tx for aspirin toxicity
IV sodium bicarb
severe cases: hemodialysis
tx for methanol, ethylene glycol toxicity
fomepizole - competes for alcohol dehydrogenase
tx for benzodiazepine toxicity
flumazenil - blocks site of benzo action
tx for beta-blocker toxicity
glucagon - acts on cardiac cells to raise intracellular cAMP independently of beta-adrenoceptors
how does NAC work?
increases glutathione stores –> combines directly w/ acetaminophen’s reactive metabolite
