Environmental/Toxins

Question 1

Indications to induce emesis

Answer 1

1. Following a recent toxin ingestion (<1-2hrs) in a asymptomatic patient
2. With unknown time of toxicant ingestion in an asymptomatic patient
3. Following ingestion of a product known to stay in the stomach for a long period of time in asymptomatic patient (eg: bezoar, massive ingestion, grapes/raisins, chocolate, wads of xylitol gum, FB, etc.)

Question 2

Contraindications to induce emesis

Answer 2

1. Ingestion of caustic or corrosive agents (batteries, bleach, lye, oven cleaning chemicals)
2. Ingestion of hydrocarbons or petroleum products
3. In patients with a decreased gag reflex (sedation, coma, symptomatic) or with decreased seizure threshold that will be unable to protect airway
4. Patients at risk for aspiration (megaesophagus, lar par, upper airway disease)
5. Brachycephalics consider gastric lavage rather than induction of emesis
6. Species that cannot vomit or is not safe to induce emesis chemically (birds, rabbits, ruminants, horses, and rodents)

Question 3

Only at home method of emesis induction for dogs? Why not in cats?

Answer 3

3% Hydrogen peroxide: acts as a direct gastric irritation in the stomach. 1-2mL/kg PO once, repeat if needed. Max dose 50-150mL/large dog. Can cause GIT irritation and ulceration so antacid therapy should be used. Cats: NOT recommended due to hemorrhagic gastritis that can be fatal

Question 4

How does apomorphine work?

Answer 4

Acts in CNS on the CRTZ to cause vomiting. Dose: 0.02-0.04mg/kg IV or IM

Question 5

What is the drug of choice for emesis induction in cats?

Answer 5

Dexmedetomidine due to its alpha-2 adrenergic agonist properties. Can cause respiratory depression, hypotension and excessive sedation. Dose: 7-10mcg/kg IM

Question 6

Indications for gastric lavage

Answer 6

1. In a symptomatic patient where emesis cannot be performed due to risk of aspiration
2. With toxicants that have a narrow margin of safety that may still require decontamination with a controlled airway (baclofen, macrocyclic lactones, metaldehyde, marijuana, organophosphates, carbamates, Ca channel blockers, B blockers)
3. Toxicants that result in bezoar formation or concretion (unbaked yeast, bread dough, prenatal iron tablets, bone meal, etc.)
4. Ingestions approaching LD50

Question 7

Complications of gastric lavage

Answer 7

Aspiration, arrhythmias, laryngospasm, electrolyte changes, conjunctival hemorrhage

Question 8

Toxins that do not bind activated charcoal

Answer 8

All the -ols!

Ethylene glycol, xylitol, ethanol, other alcohols, hydrocarbons (petroleum distillates, etc.), metals (lead, copper, zinc, arsenic, lithium)

Question 9

How does activated charcoal work? How often should be used? Side effects?

Answer 9

Activated charcoal must come into physical contact to work (like sponge), so better to give sooner since delaying reduces effectiveness. Should NOT be used in multiple doses unless toxin has long half life, known enterohepatic recirculation. Can cause hypernatremia (may be life threatening), hypokalemia, metabolic acidosis, hypermagnesemia

Question 10

How does cholestyramine work? What drugs is it used for? Side effects?

Answer 10

Anion exchange resin that binds to lipoprotein and bile acids and helps excretion of bile acids and interrupts enterohepatic recirculation.
Used for: Vitamin D, sago palm, phenobarbital, tetracycline, pen G, anticoagulants, chlorothiazide, digitalis, B blocker, NSAIDs, pesticides, E. coli enterotoxin, blue green algae, anything lipophilic.
Side effects: nausea, hypoproteinemia, constipation, steatorrhea, loss of fat soluble vitamins