Inducing vomiting – 5 examples of when it helps

In this article we look at some of the more common items that when swallowed, benefit from induced emesis

Posted: 08 December 2017

Inducing vomiting – 5 examples of when it helps


Making an animal vomit after eating a poison can be particularly important for those toxins with a high risk of causing morbidity and mortality. By inducing emesis we aim to remove as much of the ingested toxin as possible from the stomach before it can be absorbed or pass into the intestinal tract.

It’s most effective within the first couple of hours, but in cases of large quantities of high risk foods being eaten (eg, chocolate, grapes, raisins), induction of emesis can still be useful up to 12 hours after the ingestion, especially if there is radiographic evidence of the contents within the stomach.

In this article we look at some of the more common items that when swallowed, benefit from induced emesis.

1. Anticoagulant Rodenticides

For up to 7 days after the ingestion of anticoagulant rodenticides, severe coagulopathies can develop as a result of the enzyme required to activate clotting factors in the liver, vitamin K epoxide reductase, being antagonised.

Uncontrolled bleeding can be life-threatening and must be treated aggressively with oxygen, transfusions and vitamin K supplementation.

Affected animals should receive vitamin K supplementation for up to 6 weeks or until the prothrombin time is back to normal.

To avoid this, induction of emesis within 6 hours of the anticoagulant rodenticide being eaten is recommended. Following emesis, dose with oral activated charcoal to reduce absorption and help the removal of any remaining rodenticide.


2. Chocolate

Methylxanthines found in chocolate are toxic to dogs and cats, the levels of which vary in concentration depending on the type of chocolate.

Theobromine is considered toxic when eaten in quantities greater than 20 mg/kg. Look for signs such as vomiting, diarrhoea, hyperactivity, restlessness, incoordination, tachycardia, and cardiac arrhythmias. Seizures can occur when levels in excess of 50 mg/kg are consumed.

On arrival at the practice, attempts to remove chocolate from the stomach is best achieved using drugs to promote vomiting. This is then followed up by administration of activated charcoal.

Theobromine undergoes enterohepatic recirculation, so repeated doses of activated charcoal are recommended.

Unusually, emesis can still be effective up to 6 hours after the chocolate is swallowed as it can remain in the stomach for some time, particularly if it’s still in the tinfoil wrapping.

Relative Theobromine levels in chocolate

  • Milk chocolate (200mg/100g)
  • Semisweet chocolate (1000mg/100g)
  • Cocoa powder (2,800mg/100g)
  • Cocoa beans (>3,000mg/100g)

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3. Grapes and Raisins

Grapes and raisins are associated with the development of acute kidney damage in dogs. Any quantity could lead to renal failure as the number of grapes eaten doesn’t correlate with the level of damage. The toxin within the grapes or raisins is still unknown.

Signs of acute kidney injury usually develop within 24 hours unless early induction of emesis is carried out. It’s also recommended that you provide activated charcoal and intravenous fluids.


3. Xylitol

The popular sweetener xylitol is widely available in chewing-gum, sweets, vitamins, dental products, and low glycemic–index diabetic foods.

When eaten by dogs in relatively small amounts (50 to 100 mg/kg), it can causes excessive insulin release leading to hypoglycemia, weakness, lethargy, and seizures. If large quantities are consumed it can cause acute liver failure and coagulopathies.

Rapid decontamination using drugs to induce emesis is important. Unlike with chocolate, activated charcoal is not effective as it can’t bind with xylitol because of its small molecular size.


4. Human Pain Killers

Human over-the-counter medications are by far the most common reported toxin swallowed by domestic pets.

Acetaminophen (paracetamol) is the most common, followed by ibuprofen. Both of these are readily found in most households and can cause serious signs if swallowed and not treated. An animal reported to have eaten some should be considered as an emergency.

Paracetamol can cause methemoglobinemia at doses as low as 10 to 50 mg/kg in cats or acute liver failure at doses >200 to 500 mg/kg in dogs.

Ibuprofen can cause severe gastric ulceration, acute renal failure, liver damage and neurological signs.

Should a cat or dog ingest a toxic dose of paracetamol or ibuprofen, emesis induction should be induced as soon as possible. It’s especially important in cases where fast-acting medications (gelcaps) that are rapidly absorbed from the stomach.

After emesis, repeated doses of activated charcoal should be given for a couple of days to ensure the adsorption of any remaining medication.


5. Other human drugs that benefit from induced emesis

  • Benzodiazepines
  • Beta-blockers
  • ACE Inhibitors
  • Antidepressants
  • Birth control drugs
  • Statins


Find out more about the effects of these drugs on pets >


There are times when you shouldn’t rush to induce vomiting

  • Sedated or symptomatic patients – some toxins will cause sedation, increasing the risks of aspiration pneumonia during emesis.
  • Upper respiratory disease – brachycephalic dogs with ling soft palates may be at risk from aspiration pneumonia if vomiting is induced.
  • Laryngeal paralysis – take extreme care with older breeds known to acquire this condition.
  • Megaoesophagus – you’ll probably be aware of these patients in your practice.
  • Caustic or corrosive substances – if vomiting is induced you’ll cause severe damage to the oesophagus.
  • Hydrocarbons – gastric lavage is preferred to remove these agents to avoid oesophagitis and aspiration.


Use the VPIS

If you suspect a dog, cat, rabbit or ferret has eaten some human medicines, get as much information as possible and contact the Veterinary Poisons Information Service (VPIs). They provide a 24 hours information service for veterinary professionals worldwide handling animal poisoning cases.