Poisoning is common in dogs because of their habit of rapid consumption of unusual foods

 It is important to remember to keep chocolate, cakes and chocolate-coated goodies safely away from your pets

There is no antidote for chocolate poisoning. The patient needs to be hospitalized for supportive treatment and observation

Our emergency team is available 24 hours daily, seven days a week, to treat any type of emergency case, including chocolate toxicity

What is chocolate toxicity?

• Chocolate toxicity (poisoning) is caused by excessive intake of the methylxanthine alkaloids in chocolate, coffee, tea and caffeinated sodas. The active ingredient in chocolate is theobromine. The poisoning affects many organ systems and animals of all ages are susceptible.
• Poisoning is common in dogs because of their habit of rapid consumption, particularly puppies and young dogs as they may be more likely to ingest large amounts of unusual foods. Although dogs are the most susceptible, the toxin has been known to affect or kill cats, birds, rodents and reptiles as well.
• Toxic dosages for dogs :
  • Below is a list of potentially dangerous doses of chocolate. Please note that these are approximate amounts only. Every animal has varying levels of sensitivity to theobromine. Caffeine will enhance the toxicity of theobromine. Some brands of chocolate have more caffeine than others (example: Nestle's milk chocolate has 19 mg caffeine per oz versus Hershey's milk chocolate has 8 mg caffeine per oz).

Clinical signs

• The clinical signs include vomiting, diarrhea, hyperactivity, restlessness, excessive urination, muscle tremors, tachycardia, bradycardia, arrhythmias, hyperthermia (high temperature), seizures, coma and death. Vomiting and diarrhea can occur 2 to 4 hours after intake. Advanced signs (seizures, heart failure, coma and death) can occur 12 to 36 hours after intake.

Diagnosis

• The patient may have a history of exposure to a methylxanthine. The clinical signs are important, but chocolate toxicity can look similar to many poisonings such as that caused by strychnine, amphetamines, pesticides and some rodenticides. The stomach contents, serum, or urine can be analyzed for the presence of methylxanthine alkaloids (caffeine, theophylline, and theobromine).

Treatment  

• If your pet has just ingested chocolate, induce vomiting with hydrogen peroxide. Emetics (medications that induce vomiting) are contraindicated if the pet is twitchy, unaware of his/her surroundings or seizuring. Induction of vomiting in dogs can be performed with 3% hydrogen peroxide 1 ml/lb by mouth (max dose is 45 ml or 3 tablespoons). If the patient does not vomit within 15 minutes, give the same dose again. If this is not effective, a veterinarian may choose other drugs to induce vomiting.
• Take your pet to an emergency facility immediately.
• Supportive treatment: There is no antidote for chocolate poisoning. The patient needs to be hospitalized for supportive treatment and observation.
• Activated charcoal may be administered every 3-4 hours to reduce the serum half–life of methylxanthines.
• Intravenous fluid therapy may be used to help flush out the toxins.
• In some cases oxygen therapy may be needed.
• Sedation is necessary for some patients that are very hyperactive.
• The patient’s cardiovascular system function may require monitoring with ECG, blood pressure, oxygen saturation and/or blood gases.
• Medication may be required to treat a slow, very fast, or irregular heart beat.
• Insulin administration may be beneficial to treat caffeine poisoning, as insulin has been shown to be antagonistic to caffeine.

Potential complications  

• If a 50 mg/kg dose of theobromine is ingested, cardiotoxicity (heart complications) can be seen. At 60 mg/kg, seizures are possible. Any dose over 40 mg/kg should be considered life-threatening. 100mg/kg is the LD50 meaning that at this dose half of the animals will die. Animals can die from exposures well below the LD50. Pregnant or nursing animals are at risk for teratogenesis of newborns or stimulation of nursing neonates.

Aftercare (home care)  

•  It is important to remember to keep chocolates, chocolate cakes and chocolate-coated goodies safely away from your pets.

Prognosis

• Patients usually recover with aggressive supportive therapy under the direction of a veterinarian. If the ingestion and the treatment are performed in the first 4 hours, the prognosis is good. Heart failure, weakness, seizures, coma and death can occur 12 to 36 hours after ingestion and the prognosis may be guarded.

References  

• Glauberg A, Blumenthal HP. Chocolate toxicosis in dogs. J Am Anim Hosp Assoc 1983; 19: 246-248.
• Hooser SB, Beasley VR. Methylxanthine poisoning (chocolate and caffeine toxicosis) In Kirk RW, ed Current veterinary therapy IX. Small animal practice. Philadelphia: Saunders, 1992.
• Osweiler, Gary D., Methylxanthine alkaloids, Toxicology (The national veterinary medical series for independent study), Williams & Wilkins 1996.
• Tilley LP, Smith FWK, Chocolate toxicity, In: The 5 – minute veterinary consult canine and feline, Lippincott Williams & Wilkins third edition 2003.
• Plunkett SJ. Chocolate and methylxanthine toxicosis In Emergency Procedures 2nd Ed. Philadelphia: Saunders, 2002; pp 308-309.