VPT 421: Veterinary Toxicology (2+0)

DELAYING FURTHER ABSORPTION WITH EMETICS

• Delay further absorption of the toxicant by the use of emetics. However, emesis is of value in dogs, cats, and pigs if done within a few hours of ingestion.
• Emetics are also contraindicated in rodents, rabbits, horses and ruminants because they cannot vomit safely and effectively.
• Emesis is contraindicated when
  • the swallowing reflex is absent
  • the animal is convulsing
  • the animal is sedated
  • corrosive agents, volatile hydrocarbons, or petroleum distillates are involved
  • risk of aspiration pneumonia is imminent.
• Local and central emetics can be used to induce emesis.
• Local emetics like saturated salt solution, powdered mustard, crystals of washing soda are useful.
• Central emetics like apomorphine, xyalzine and tincture of ipecacuanha can also be used. Sodium chloride 1-3 teaspoons in a cup of luke warm water can be used.
• Emesis can also be produced by placing a teaspoonful of common salt on the back of the tongue, administering crystals of sodium carbonate (washing soda), mustard and water or administering 10-60 ml of 1% copper sulphate solution.
• Ipecacuanha

  • Ipecacuanha acts both as a central and local (reflex) emetic.
  • It irritates the gastric mucosa and within 15-30 minutes after administration, emesis is observed.
  • It produces a toxic metabolite and hence if emesis does not occur after administering the syrup, it should be removed by administering a gastric lavage.
  • High concentrations of ipecac are cardiotoxic.
  • Animals with ipecac overdose may exhibit arrhythmias, hypotension and myocarditis.
  • In dogs 10-20 ml of ipecacunha and in cats 2-5 ml of ipecacuanha will be useful.
  • Activated charcoal (a constituent of universal antidote) should not be administered with ipecac as the charcoal adsorbs the syrup of ipecac and prevents it from irritating the gastric mucosa and in turn producing emesis.
• Hydrogen peroxide is used as 3% solution and is most effective if the stomach contains ingesta. H₂O₂ at 1 ml/kg orally is also successful.
• Copper sulphate in a concentrated form is not recommended as it is an irritant and facilitates absorption of poison.
• Apomorphine can be administered at the rate of 0.05 – 0.1 mg/kg. Apomorphine is contraindicated in cats and pigs.
• Xylazine can be administered, as a central emetic in cats.