Why Is It Toxic?
The toxic compounds in chocolate are methylxanthines – this includes both theobromine and caffeine. These compounds inhibit cellular receptors, stimulate the central nervous system, and enhance cardiac and skeletal muscle contractility. In addition, the high fat content in chocolate leads to local gastrointestinal irritation (vomiting and diarrhea), and in severe cases, a serious disease called pancreatitis. Clinical signs occur within 12 hours, but most pets will begin exhibiting signs within 1-4 hours of ingestion.
Different types of chocolate have different amounts of theobromine and caffeine. Relative amounts of methylxanthines in chocolate are as follows:
|
Compound |
Theobromine (mg/oz) |
Caffeine (mg/oz) |
| White chocolate | 0.25 | 0.85 |
| Milk chocolate | 58 | 6 |
| Dark chocolate | 130 | 20 |
| Semi-sweet chocolate | 138 | 22 |
| Baker’s unsweetened chocolate | 393 | 47 |
| Dry cocoa powder | 737 | 70 |
While we generally consider 100 mg/kg to be a toxic dose, some patients will exhibit clinical signs at a dose as low as 20 mg/kg. However, often, we don’t know the type or amount of chocolate that was ingested, so it is best to proceed as if the ingestion was the worst-case scenario.
Treatment
Treatment depends on the amount of methylxanthines ingested, the time of ingestion, and the patient’s clinical signs. If recent ingestion occurred, vomiting is induced to evacuate the stomach. In severe cases, sedation and gastric lavage with a stomach tube may be performed to evacuate the stomach contents. Activated charcoal is administered to bind the toxins in the gastrointestinal tract. Fluid therapy, anti-vomiting medications, gastrointestinal protectants, and a bland diet may be prescribed. In severe cases, patients require intensive care including intravenous fluid therapy, continuous EKG monitoring, oxygen support, urinary catheterization, and intravenous medications to manage seizures, cardiac arrhythmias, and abnormal respirations.
Prevention
If treated promptly, most patients with chocolate toxicity recover, but it is important to understand that chocolate ingestion can lead to severe complications and even death. It is best to avoid chocolate ingestion in your pet. During the holidays (Halloween, Valentine’s Day, and Easter) when chocolate is abundant, make sure it is kept out of reach of your pet. If you suspect ingestion, contact your veterinarian immediately.
Written by Jennifer Blair, DVM