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what is activated charcoal?
organic matter → wood pulp, vegetable matter; first burned, then oxidized to increase number of pores
activated charcoal pores
huge number of pores
huge surface area
50 grams has surface area of 10 football fields
the efficacy of activated charcoal depends on
time after ingestion of toxin
how long it stays in the GI tract
toxin to AC ratio
stomach contents
quality of AC product
toxin-AC can start to desorb after
30 minutes
what is the optimal toxin to AC ratio?
1:10
what are the lavage limits?
5-10 ml/kg
prepared AC formulations
already in liquid solution
bottles or tubes
vet products → toxiban, liquichar
prepared AC formulations can contain other ingredients like
sorbitol, kaolin, propylene, glycerol
when should you give AC?
the sooner the better
best results are within 30 minutes of toxin ingestion
true or false: it’s never too late to give AC as long as any toxin remains in the GI tract.
true
for toxins excreted via biliary system, AC can help even if
the toxin entered the body by route other than ingestion
giving AC before inducing emesis or performing lavage
starts binding toxin right away
increases contents in stomach, improves emesis
can’t use vomit or lavage for analysis
must repeat after emesis or lavage is complete
giving AC after emesis or lavage
less toxin to bind up all available sites on AC
vomit or lavage fluid can be used for analysis
hypernatremia and AC
can be associated with AC alone
no specific product association yet identified
thought to be more common in very small patients, mostly small dogs
what are adsorbing agents other than AC?
kaolin, pectin, bentonite, bismuth, ion exchange resins, products sold as “mycotoxin binders”
what is the goal of enhancing elimination?
to remove as rapidly as possible any toxin that has already been absorbed into the systemic circulation and tissues
to diminish degree and duration of toxic effects
major methods of enhancing elimination
diuresis (urinary excretion)
decrease enterohepatic recycling (biliary excretion) → multiple doses of activated charcoal
intravenous lipid emulsion treatment
use products designed for parenteral nutrition
mechanism not well understood
examples → moxidectin, ivermectin, lipophilic drugs
what is the lipid sink theory?
lipid in blood draws lipid soluble toxin out of system and binds in blood
systemic chelators
enhances elimination of absorbed toxin by altering diffusion gradient
examples → metal chelators use for various metal poisons
alteration of metabolism
prevention of toxic metabolite formation
example → ethylene glycol
what is an antidote?
an agent that reacts with the poison or its receptor or interferes with its metabolite pathway to decrease the ability of the poison to cause toxicity
what overlaps with other steps like decontamination and enhancing elimination?
antidotes
universal antidote
NOT antidotes
contain a mixture of AC, kaolin, magnesium oxide, tannic acid, and other stuff
not superior to AC!
universal animal antidote
labeled dosage on product does not provide enough AC to patient
what are the antidote mechanisms?
block receptors used by the toxin → atropine blocks ACh receptors in organophosphate or carbamate poisoning
inhibit metabolism of original substance to a toxic metabolite
true or false: there are a lot of antidotes that exist.
false