Chocolate Toxicity Table

                            Milk Chocolate (60 - 66 mg/oz or 2.12 - 2.33 mg/gram of methylxanthines)

Semi Sweet Chocolate (150 mg/oz or 5.29 mg/gram of methylxanthines)

Baking Chocolate (~450 mg/oz or 15.87 mg/gm of methylxanthines)

NOTES:
* Mild reactions may be seen at ~ 20 mg/kg

* Moderate to severe reactions may be seen at doses over 40 mg/kg

* Cardiotoxicity may be seen at ~ 50 mg/kg

* Seizures are possible at doses over 60 mg/kg

* Any dose over 40 - 45 mg/kg should be considered potentially life-threatening

* 100 mg/kg is the LD50, meaning that at this dose half of the animals will die; animals can die from exposures well below the LD50

Cocoa beans may contain up to 255 mg theobromine per ounce of beans, although the exact amount will vary due to natural variation of the cocoa beans. The LD50's of theobromine and caffeine are 100-300 mg/kg, but severe and life threatening clinical signs may be seen at levels far below these doses. Based on NAPCC experience, mild signs have been seen with theobromine levels of 20 mg/kg, severe signs have been seen at 40-50 mg/kg, and seizures have occurred at 60 mg/kg. Accordingly, less than 2 ounces of milk chocolate per kg is potentially lethal to dogs.

Clinical signs occur within 6-12 hours of ingestion. Initial signs include polydypsia, bloating, vomiting, diarrhea, and restlessness. Signs progress to hyperactivity, polyuria, ataxia, tremors, seizures, tachycardia, PVC's, tachypnea, cyanosis, hypertension, hyperthermia, and coma. Death is generally due to cardiac arrhythmias or respiratory failure. Hypokalemia may occur later in the course of the toxicosis. Because of the high fat content of many chocolate products, pancreatitis is a potential sequela.

Management of chocolate ingestion includes decontamination via emesis followed by gastric lavage. Because methylxanthines undergo enterohepatic recirculation, repeated doses of activated charcoal are usually of benefit in symptomatic animals (vomiting may need to be controlled with metaclopramide). Intravenous fluids at twice maintenance levels will help maintain diuresis and enhance urinary excretion. Because caffeine can be reabsorbed from the bladder, placement of a urinary catheter is recommended. Cardiac status should be monitored via EKG and arrhythmias treated as needed; propranolol reportedly delays renal excretion of methylxanthines, so metoprolol is the beta-blocker of choice. Seizures may be controlled with diazepam or a barbiturate. In severe cases, clinical signs may persist up to 72 hours.