Toxicology Flashcards
Antidote for arsenic?
dimercaprol, succimer, d-penicillamine
Antidote for lead?
succimer, EDTA, dimercaprol, d-penicillamine
Antidote for mercury?
dimercaprol, succimer, d-penicillamine
Antidote for black widow spider bite?
Lactrodectus antivenin
Antidote for calcium channel blockers?
calcium, glucagon, insulin + glucose
Antidote for cyanide?
nitrite + thiosulfate, hydroxycobalamin
Antidote for hydroxyfluoric acid?
calcium gluconate
Antidote for methemoglobinemia?
methylene blue, ascorbic acid
Antidote for opioids?
nalmefene, naloxone
Antidote for rattlesnake bite?
CroFab
Antidote for sulfonylureas?
ocreotide
Antidote for valproic acid?
carnitine
Antidote for TCAs?
sodium bicarbonate
Pt has taken an enteric coated, extended release drug. It’s only been 30 min. What to do?
whole bowel irrigation w/ 1-2L isotonic PEG electrolyte soln
Hemodialysis is an option for poisoning with…
methanol, ethylene glycol, lithium, salicylates, sotalol
Hemoperfusion is an option for poisoning with…
carbamazepine, phenytoin, phenobarbital, theophylline
Drugs that need quantitative serial levels?
PADlock the TV and the PC
Phenytoin Aspirin/salicylates Digoxin Theophylline Valproic acid Phenobarbital Carbamazepine
Drugs that need a single quantitative level at a set point?
MACE HIM Methanol Acetominophen Carbon monoxide Ethanol, ethylene glycol Heavy metals (24 hr urine) Iron Methemoglobin
What antidote is c/i in sympathomimetic toxicity?
beta blocker w/o alpha blocking activity
this is b/c unopposed alpha blockade is bad
give a combo blocker like carvedilol
Most toxic beta blocker?
propranolol
Membrane-depressant effects (widened QRS) of beta blockers may respond to…
sodium bicarbonate (as for TCA toxicity)
How well does calcium administration aid in treatment of calcium channel blocker toxicity?
it is most useful for negative inotropic effects, less effective for AV nodal blockade and bradycardia
IV lipid emulsion may aid in treating…
Calcium channel blocker toxicity and propranolol toxicity (lipophilic)
How does INH cause metabolic acidosis?
inhibits hepatic conversion of lactate -> pyruvate
What is a Rumack-Matthew nomogram?
computer program: give it a blood level of acetominophen and how long after overdose you are and it tells you the likelihood of hepatic toxicity
Administer N-acetylcysteine in Tylenol overdose if levels are…
> 150 mcg/mL @ 4 hours
When to discontinue N-acetylcysteine administration in acetominophen overdose?
DO NOT d/c once started. must give q4h x17
What concentration of ASA after acute poisoning indicates possibility of severe overdose?
100 mg / dL
Acute Rx of salicylate poisoning?
glucose-containing fluids to reduce risk of cerebral hypoglycemia
sodium bicarb to treat acidosis and acidify urine
add in some potassium to maintain lytes
hemodialysis for severe acidosis or severe neurological sx
Tx for inhalation of chlorine gas?
humidified O2, bronchodilators
Tx for inhalation of ammonia gas?
humidified O2, bronchodilators
Tx for inhalation of sulfur dioxide gas?
humidified O2, bronchodilators
How does cyanide cause damage?
blocks binding of O2 to cytochrome c
inhibts complex IV in ETC
How does hydrogen sulfide cause damage?
similar to cyanide: blocks binding of O2 to cytochrome c
but there is no specific antidote
smells like rotten eggs
What gas causes damage in a manner similar to cyanide but has no specific antidote?
hydrogen sulfide (smells like rotten eggs)
How does nitrogen oxide gas cause damage?
causes methemoglobinemia…
tx w/ methylene blue, ascorbic acid
How does the cyanide kit work?
contains sodium nitrite, sodium thiosulfate, amyl nitrite
the inhaled amyl nitrite + IV sodium nitrite cause formation of methemoglobin. cyanide likes methemoglobin more than cytochrome c, so it binds here. thiosulfate + cyanomethemoglobin = thiocyanate, regular hemoglobin. the thiocyanate is eliminated renally
Charcoal/gastric lavage for hydrocarbon toxicity?
nope… not usually.
charcoal isn’t used; gastric lavage may be indicated for some rare situations w/ a few select hydrocarbons that have severe toxicity
Tx for hydrocarbon toxicity?
no specific antidote
intubation for resp failure
Mg, K for arrhythmias
lidocaine or beta blockers for vfib
KEEP CALM since they’re sensitive to catecholamine release
Rx for organophosphate poisoning?
atropine + pralixodime [ProtoPam]
Rx for carbofuran poisoning?
it’s a carbamate that causes cholinergic tox
give atropine + pralixodime [ProtoPam]
What botanical insecticide can cause seizures and neurotoxicity?
pyrethrum (via inhalation or ingestion)
(and nicotine)
acts at voltage-sensitive Na, Ca, and Cl channels
can also cause contact dermatitis
tx: symptomatic support and control of seizures
What are the toxic botanical insecticides?
nicotine
pyrethrum
rotenone (GI irritation, rhinitis, pharyngitis, dermatitis)
all of these are treated w/ symptomatic support
Toxic herbicides? How to treat?
2,4-D and Paraquat
GI symptoms + bizarre or aggessive behavior (2,4-D)
MOF, lung scarring, CNS effects (Paraquat)
treat w/ fluids, sodium bicarbonate (2,4-D) and maintenance of lytes
Lab values in 2,4-D poisoning?
(herbicide)
metabolic acidosis, elevated creatine phosphokinase, possibly myoglobinuria
Difference in effects of caustic acids vs. alkalis?
acids -> coagulative necrosis. stomach is most common involved site. esophagus and oropharynx relatively resisitant
alkalis -> liquefactive necrosis. oropharynx, hypopharynx, esophagus most likely involved
Caustic acids cause (coagulative / liquefactive) necrosis.
coagulative
stomach most common involved site
Caustic alkalis cause (coagulative / liquefactive) necrosis.
liquefactive
esophagus, pharynx most common involved site
Treatment for acute caustic acid or alkali ingestion?
intubation
NO EMETICS: it’ll burn on the way up
gastric lavage
dilute alkalis if w/in 30 min (don’t dilute acids: too hot)
don’t try and neutralize: too hot
Lead inhibits which enzymes of heme synthesis?
delta-ALA dehydratase
and
ferrochelatase
What levels of lead impact brain development in a child?
10 mcg/mL
Which lead chelator may actually increase CNS lead levels?
EDTA
therefore only use with dimercaprol, which is typically used for lead encephalopathy
You’re treating someone with lead poisoning. You give them a chelating agent and after a short dip, their serum lead levels rise again. What did you do wrong?
serum levels may rise after chelation due to tissue redistribution. repeat the chelation
Heavy metal poisoning that can be measured in hair?
arsenic
Chronic exposure to this heavy metal causes dermatologic issues like palmar and solar keratoses.
arsenic
What drug is formulated in peanut oil?
dimercaprol
(IM injection q4h)
problem: hypersensitivity, G6PD deficiency, nephrotoxicity, sterile abscess at injection site, etc. etc.
Mercury toxicity causes what?
interstitial pneumonitis, intention tremor, inflammation of gums w/ excessive salivation
desquamative rash in small children
dose-related nephrotic syndrome
Which antivenin is made in horses and therefore may result in hypersensitivity reaction when administered?
lactrodectus antivenin
What happens if you take syrup of ipecac chronically?
cardiotoxicity
Why is glucagon a good antidote for beta blocker toxicity?
acts on cardiac muscle cells to increase intracellular cAMP
but does so independent of beta receptors
How does insulin help in beta blocker toxicity?
switches cardiac metabolism to glucose which improves heart muscle function….
also, since beta blockers and calcium channel blockers reduce insulin secretion (beta2 pancreatic receptors and L-type calcium channels), toxicity results in hyperglycemia, hypoinsulinemia, and acidosis. insulin helps correct this
Use metaclopramide for N/V associated w/ _______________ overdose.
acetominophen
This drug is an antihistamine with antiserotonin effects.
cyproheptadine
