“Oh no, my dog ate chocolate!” This is not an uncommon phone call to get from a concerned owner at any veterinary hospital, especially around the holidays when there is an abundance of chocolaty goodness around. Unfortunately, dogs (and cats) are very sensitive to the side effects of chocolate. Chocolate contains theobromine and caffeine, which are both classified as methyxanthines. Theobromine and caffeine are naturally occurring methylxanthines found in several plants, foods and beverages, and in several human and veterinary medications. The severity of the side effects or toxicity due to the toxin components of the chocolate is based on the amount and specific type of chocolate ingested. Depending on the dose ingested, we can see side effects ranging from hyperactivity to increased heart rate, vomiting, diarrhea, tremors, weakness, or even seizures.
Theobromine is obtained from the plant Theobroma cacao and is the primary toxic component (along with caffeine). Milk chocolate is derived from the seeds of the Theobroma cacao plant after fermentation and roasting. Milk chocolate contains 44 mg/ounce of theobromine. Thus a 4.5 ounce Hershey bar has about 240 mg of theobromine. Unsweetened baking chocolate on the other hand contains approximately 10 times as much theobromine at 440mg/ounce and is thus much more dangerous. A general rule of thumb is the more bitter the chocolate the more toxic it could be. Mild symptoms from chocolate ingestion can be seen at doses of 20mg per kilogram of body weight, moderate effects at 40mg per kilogram, and severe effects at 60mg per kilogram (1lb = 2.2kg).
Treatment of chocolate ingestion involves induction of vomiting to remove as much of the chocolate from the stomach as possible if the ingestion is recent, administration of activated charcoal to help decrease absorption of the remaining chocolate in the digestive system, and symptomatic treatment of other side effects and vitals monitoring: gastroprotectant medications for vomiting and diarrhea, sedative for agitation and elevated heart rate, IV fluids, monitoring for heart arrhythmias (abnormal heart rhythms), frequent walks as the toxins are eliminated in the urine, muscle relaxants for tremors, and treatment of seizures with anti-convulsant medications if they occur. Depending on the type and amount of chocolate ingested the pet may need to be kept in the hospital for treatment or they may be able to be treated on an outpatient basis. Most dogs if treated appropriately do very well. Occasionally no treatment is necessary if the dose ingested is very small.
Since the toxic side effects of chocolate can be significant depending on the type and dose ingested, if your pet has ingested chocolate the best thing to do is to call your veterinarian or the Animal Poison Control Hotline at 1-888-426-4435 for further advice on treatment.