Toxicology Flashcards
what are the primary determinants of toxicity?
- dose (main determinant)
2. time
who is the father of modern toxicology & said that the right dose differentiates a poison & remedy?
Paracelsus
what is the LD50?
lethal dose at which 50% of animals dies
what is the legal definition of a poison?
LD50 under 50 mg/kg bwt
tx index?
LD50/ED50–>the larger the #, the safer the drug
what is ALD?
average lethal dose: estimated from accidental deaths in humans
steps in clinical management of poisoning
- ABC
2. reduce drug in body to decr time of exposure
if tx’ing an unconcsious patient that you think may have OD’d?
- glu if suspect hypoglycemia
- insulin if suspect diabetic shock
- naloxone if suspect narc OD
what are toxidromes?
known toxicology standards
what can be used to induce emesis?
- apomorphine
2. syrup of ipecac
how does charcoal work to reduce toxicity in body?
large SA–>toxicants bind–>prevents absorption of these toxicants
what component do chelating agents typically have?
sulfates–>bind the heavy metal
how to tx lead poisoning
DMSA
what is the drug of choice for ethylene glycol or methanol toxicity?
fomepizole
cherry red appearance of the lips and gums
COHb 40-60%
what is the antidote for too much warfarin?
vitamin K (phytonadione)
what is the antidote for methemoglobinemia?
methylene blue
MOA: tx causes a direct chemical reduction of methemoglobin back to hgb
methylene blue
what are toxidromes?
well characterized clinical syndromes that provide a sx fingerprint for assc’d intoxicants
hallucunations, paranoia, mydriasis, HTN, tremor, hyperthermia
cocaine, amphetamines, PCP
coma, decreased respiration, miosis or mydriasis, hypotension
alcohol, barbituates, benzos
coma, respiratory depression, pinpoint/miosis, hypothermia, hypotension, histamine release
opioids
what is the opiate triad?
hypothermia, hypotension, histamine release
agitation, mydriasis, fever, sry skin, flushing, urinary retention
anticholinergics, antidepressants
fasciculation, incontinence, salivation, wheezing, lacrimation, bradycardia
organophosphates, nicotine
coma, agitation, mydriasis, dysrhytmia, convulsions, hypotension
TCA
incr respiration, diaphoresis, tinnitis, agitation, alkalosis (early), acidosis (late), hyperpyrexia
salicylates, ASA,
Dilated pupils due to antimuscarninic effects, increased HR
meperidine (opioid with diff effects than others)
what to use to tx benzo OD?
flumazenil
what is the most potent poison known?
botulism
how to tx cyanide poisonin (3 steps)
- inhale amyl nitrate
- IV sodium nitrate
- IV sodium thiosulfate
which component of cyanide antidote: oxidize a portion of Hb iron from ferrous state to ferric state, converting Hb to methemoglobin
nitrates (step 1-2)
which component of cyanide antidote: react with cyanmethhemoglobin to give thiocyanate & Hb?
sodium thiosulfate (step 3)
what can be a lifesaving adjunct for methanol and ethylene glycol poisoning?
hemodialysis (esp use in patients who are sx)
what is the drug of choice for methanol and ethylene glycol poisoning?
fomepizole
how to tx acetaminophen toxicity?
n-acetylcysteine
