Description
Chocolate toxicities are one of the most common toxicities seen in dogs. The two ingredients in chocolate that pose a problem for dogs are caffeine and theobromine.
Caffeine and theobromine are methylated xanthine alkaloids of plant origin. Caffeine is present in most chocolates, in concentrations approximately 10% of the theobromine content. Theobromine is found in cacao beans (Theobroma cacao) and is present in products made from cacao. Amount of theobromine in cacao beans varies naturally with growing conditions and varietal strain of T. cacao. Final methylxanthine content (caffeine plus theobromine) of cacao-derived products also varies with degree of processing (Figure, Table).
Methylxanthines are rapidly absorbed from the gastrointestinal (GI) tract, although fat present in chocolate products may slow absorption. The half-life of theobromine is approximately 17.5 hours and the half-life of caffeine in dogs is about 4.5 hours. Methylxanthines cross the placenta and are excreted into milk, so unborn or nursing pups may be affected by chocolate toxicosis.
The effects of methylxanthines include central nervous system (CNS) stimulation; enhanced force and rate of cardiac contraction; increased gastric secretion; smooth muscle relaxation (particularly bronchial) and diuresis (increased or excessive production of urine).
Some dogs tolerate higher doses than others. Effects from caffeine begin within 30-60 minutes after ingestion. Theobromine effects may manifest around 2 hours after ingestion and central nervous system and cardiovascular signs will predominate. Gastrointestinal signs, often due to pancreatitis, often follow due to the high fat content.
If the chocolate contains xylitol, a common artificial sweetener, then additional problems such as hypoglycemia (low blood sugar) and liver failure.
Testing Your Veterinarian Will Likely Recommend:
Complete Blood Count:
Dehydration often occurs because of the diuretic nature of methylxanthines and gastrointestinal symptoms of vomiting and diarrhea.
Biochemistry Profile:
No specific biochemistry abnormalities are expected, however, low potassium, elevated glucose, elevated lactate and liver enzyme elevations have been described.
Urinalysis:
Urine-specific gravity may be decreased due to diuresis or increased due to dehydration.
EKG:
Your vet will want to monitor for arrhythmias
Blood Pressure:
Your vet will monitor for hypertension and hypotension.
Clinical Symptoms of Toxicosis:
Dosages of methylxanthines <20 mg/kg are unlikely to cause significant symptoms.
Dosages of 20-40 mg/kg can cause mild to moderate sign such as:
- Vomiting
- Excessive urination
- Diarrhea
- Restlessness.
Dosages of 40-50 mg/kg may result in:
- Agitation
- Hyperactivity,
- Imbalance
- Urinary incontinence
- Elevated heart rate
- Elevated respiratory rate
- Elevated blood pressure
- Increased body temperature
At higher dosages, severe symptoms such as:
- Tremors
- Seizures
- Cardiac arrhythmias
- Low blood pressure
- Coma
- Death
Dosages >60-80 mg/kg are usually associated with seizures.
TREATMENT
It is important to take chocolate toxicity seriously and pursue veterinary care immediately following ingestion. Call poison control at (888) 426-4435 on your way to the emergency vet.
Immediate Treatment
-
Decontamination
If the dog is asymptomatic and has not already vomited, induction of vomiting is a good first step. Emesis may be effective as late as 4-6 hours following ingestion due to slow absorption of chocolate. The administration of one of the following:
- Apomorphine can be given at 0.02-0.04 mg/kg IV or a single tablet can be crushed and placed into the conjunctival sac of one eye, with tablet residue flushed out as soon as vomiting occurs. If you bring your dog to the vet we give this intravascularly.
- Hydrogen peroxide 3% can be given at 2 mL/kg PO (maximum 45 mL) and may be repeated once. Make sure hydrogen peroxide is active, i.e. it should bubble and fizz. Feeding a few pieces of bread prior to administration provides bulk that may increase vomiting and aid in a more thorough evacuation of the stomach. Note that risk exists of esophagitis, hemorrhagic gastritis, and air embolism. Because of such risks, I recommend avoiding this modality if possible. Getting your dog to the vet as quickly as possible and having them use apomorphine for emesis is a safer plan.
For asymptomatic patients that have ingested small to moderate amounts of chocolate, fasting followed by a bland diet is usually adequate. After an 8-hour fast, I recommend starting with either canned organic pumpkin or baked sweet potato mixed with plain psyllium husk and warm water or bone broth. The dosage of plain psyllium husk is 1 teaspoon per 20 lbs of body weight, which is very effective in preventing and controlling associated diarrhea. Twelve hours after this initial meal, you can add gently cooked ground turkey for the next 3-4 meals. As long as the stools are normal, appetite is good, and there is no vomiting after this period, you can gradually transition back to their regular diet.
Activated charcoal can be also administered at 1-3 g/kg PO. In cases of very high methylxanthine exposure, activated charcoal can be repeated at 8-12-hour intervals as long as the patient remains symptomatic. If your veterinarian plans to give several doses they should monitor carefully for hypernatremia and other electrolyte abnormalities before each additional dose.
To manage diarrhea and nausea symptoms at home: Remedies that can help soothe gastrointestinal upset include L-Glutamine, Marshmallow Root, and Slippery Elm. You can make a ginger tea for your dog can also help settle the stomach and curb any nausea. Bentonite clay is great at binding to pathogenic bacteria in the gut and is a great treatment for diarrhea.
For patients that ingest higher doses more aggressive treatment may be required.
Gastric lavage may be recommended in large ingestion cases if emesis is contraindicated or does not yield results.
IV fluid therapy is important to maintain venous access for drug administration, provide cardiovascular support, and promote diuresis to enhance methylxanthine excretion. Antiemetics may be administered if the vomiting is severe. It is important to note that caffeine can be reabsorbed across the bladder wall, which may prolong the duration of clinical signs. Therefore, in severe cases, urinary catheterization or frequent walking to encourage urination is recommended to keep the bladder as empty as possible.
Seizures – This is an unlikely result of chocolate toxicosis with large quantities needed to be ingested in order to see this symptoms. Initially, management of any seizures will be treated with diazepam or midazolam intravascular injections. If these medications are ineffective in stopping seizures then other options may become necessary such as:
1. Propofol 3-6 mg/kg IV or 0.1-0.6 mg/kg/min IV as a continuous rate infusion (CRI)
2. Phenobarbital 4-16 mg/kg IV to effect.
3. Inhalation anesthesia
Tremors: If tremors are present without seizures, a muscle relaxant such as methocarbamol may be given.
Arrhythmias– Ventricular tachyarrhythmias are treated with lidocaine. On the other hand, sinus tachycardia, supraventricular tachycardia, and refractory arrhythmias may be managed with beta-blockers.
PROGNOSIS
Prognosis varies depending upon the type of chocolate, quantity ingested, body weight of the dog, and the time between ingestion and the initiation of treatment. In most cases, treatment is successful.
In a report of 44 dogs with chocolate toxicosis, 43 were successfully treated and discharged, while one dog sadly died. The dog that died had a calculated dose of 64 mg/kg of theobromine and 19.7 mg/kg of caffeine and was presented 12 hours after ingestion with tachycardia, hyperthermia, seizures, vomiting, and hypokalemia. This underscores the importance of prompt intervention in cases of high doses of chocolate ingestion.
Let’s Sum It Up
- Chocolate toxicity should be taken seriously in dogs. Start by calling the poison control hotline.
- Home remedies to keep in the cabinet include: activated charcoal, hydrogen peroxide, powdered ginger, organic psyllium husk , canned organic pumpkin and bentonite clay.
- The two ingredients in chocolate that pose a problem for dogs are caffeine and theobromine.
- Symptoms include but are not limited to vomiting, diarrhea, agitation, urinary incontinence, muscle tremors and seizures.
- Pancreatitis is a common secondary issue to chocolate ingestion.
- Hospitalization is often necessary in moderate to severe cases.
- If the chocolate contains the artificial sweetener, xylitol, additional symptoms such as hypoglycemia and liver failure can occur.
