Caffeine and theobromine are alkaloids of plant origin found in a variety of foods, beverages, dietary supplements and over the counter products. Intoxication of animals most often occurs following the ingestion of chocolate (containing primarily theobromine, but also caffeine), caffeine containing dietary supplements or over the counter stimulant tablets. Less frequently, dogs have reportedly been intoxicated following the ingestion of coco bean shells used as mulch for plants.
The Theobromine content of chocolate varies, with unsweetened baking chocolate containing 1360-1600mg/100g and milk chocolate containing 155-212mg/100g. The lethal doses of caffeine and theobromine for dogs vary from 110-200mg/kg and 100-250mg/kg, respectively.Most cases of intoxication occur in dogs. Dogs may be predisposed to intoxication from theobromine due to slower metabolism. The half life of theobromine in dogs is approximately 17.5 hours compared to 6-10 hours in humans.
Signs initially are restlessness, hyperactivity, behavioural abnormalities and emesis. Signs progress rapidly to panting, tachycardia, weakness, ataxia, diuresis, diarrhoea, hyperexcitability, severe hyperactivity, muscle tremors, hyperthermia and clonic seizures.
Your dog should be taken to your closest veterinary clinic as soon as possible.