Toxicology (3) Flashcards
how do cats usually become poisoned by toxins?
coat contamination (then grooming)
ingestion of poisoned prey
what action can owners take before bring suspected to toxin cases in?
wash if toxin was topical
encourage water consumption
what should you ask thew owners of toxin cases to bring with them to the surgery?
bottle or sample of toxin
what is the first step when presented with a toxin case?
stabilise - respiratory, cardiovascular, CNS, thermoregulation
how are topical exposures to toxins treated?
wash (water and mild detergent) and clip
when washing a case that has been exposed topically to a toxin, what do you need to take care with?
ensuring the animal doesn’t become hypothermic, especially if they are already depressed/ill
how is ocular contamination of toxins treated?
lavage eye for 30 minutes with tepid saline and treat for ulceration
what is the aim of treating ingested toxins?
decrease the absorbed dose (decrease absorption, increase elimination, bind toxin)
how can we decrease the absorbed dose of toxins?
induce emesis
gastric lavage
adsorbents
how can emesis be triggered in dogs?
apomorphine
how can emesis be triggered in cats?
xylazine or dexmedetomidine
how soon should emesis be induced after toxin ingestion?
within 3 hours (as soon as possible)
what are some contraindications for inducing emesis in toxin cases?
animal already vomiting
absent gag reflex
sedation or loss of consciousness
seizuring
ingestion of corrosive substances
how does apomorphine stimulate emesis?
acting on dopamine receptors in the chemoreceptor trigger zone
how can apomorphine be antagonised?
naloxone (this is only the sedative not the emetic effect)
how can xylazine be reversed?
atipamazole
how does hydrogen peroxide induce emesis?
irritation of the stomach
why isn’t table salt recommended for inducing emesis?
cause electrolyte imbalances
what are some precautions that need to be taken when doing gastric lavage?
general anaesthetic
cuffed ET tube
lower head/neck relative to thorax
what can be used in combination with saline when lavaging the stomach?
activated charcoal
what is activated charcoal used for?
as an absorbent
how long should you waiting after inducing emesis to give activated charcoal?
at least 30 minutes to avoid them vomiting it
when do you need to give multiple doses of activated charcoal?
if they have injected a toxin/substance that undergoes enterohepatic recirculation
what is a cathartic?
stimulates defecation (laxative) so enhance GI elimination
what can be given to enhance toxin clearance? c
cathartics
enema
diuresis
what can be given to cause diuresis in toxin cases?
IVFT
furosemide
mannitol
what is the normal urine output of a patient?
0.5-1 ml/kg/hr
why should a cathartic be used after giving activated charcoal?
activated charcoal only binds weakly to toxins, so reduce the amount of time the toxins spend inside the GIT or they will be absorbed
when would cathartics be contraindicated?
if the animal already has diarrhoea
if they are dehydrated
intestinal perforation/obstruction
what are some examples of cathartics?
psyllium hydrophilic mucilloid
sorbitol
sodium/magnesium sulphate
liquid parafin
what is an antidote?
any compound that counteracts the effects of toxicants
what are the categories of antidotes?
chemical
pharmacological
function
how do chemical antidotes work?
directly on the toxin to decrease its toxicity or increase excretion
how do pharmacological antidotes work?
antagonise toxins at the target site
how do functional antidotes work?
lessen the clinical signs caused but have no effect on the actual toxin
what drug can be used to stimulate the respiratory system?
doxapram
what analgesic should be used for toxin cases?
opioids
why should NSAIDs be used in toxin cases?
damage to oral mucosa and potentially toxic
what should be used if toxin patients are having seizures?
diazepam (first line) or phenobarbital
