Dogs and chocolate Print
News - Rubrieke
Thursday, 25 September 2014 18:53
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Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

I love chocolate, especially Chuckles from Woollies. Unfortunately so does my dog Gemma. She can hear a packet open from another postal code and smell chocolate buried in a bunker.

She is my excuse that I always need to finish the packet. She will sniffle out and eat any bit of chocolate which I pack away for later. She once pulled a whole baked chocolate pudding of the table and consumed half and I must say, in retrospect, she was really not herself for a few days afterwards.
So what is the big deal about chocolate then? The severity of chocolate’s toxicity is dependent on the type of chocolate and the inherent susceptibility of the individual. Dogs with heart conditions and seizure problems are more likely to develop clinical signs.

Chocolate contains chemicals called methylxanthines: theobromine and caffeine, specifically in chocolate. Cocoa powder contains the highest levels of methylxanthines – about 27 mg/gram, baker’s chocolate about 18 mg/g, milk chocolate 6 mg/g and white chocolate a negligible 0.04 mg/g.

So, a 150 g milk chocolate slab would contain about 900 mg of methylxanthines. The symptoms will depend on the amount consumed and the susceptibility of the individual. Up to 40 mg/kg could cause mild to moderate signs, whereas 40–60 mg/kg could cause increased heart rate and arrhythmias and be potentially life-threatening. More than 60 mg/kg could cause seizures. To estimate the amount of stimulants eaten – If a 15 kg dog ate a 150 mg slab of chocolate, it would equate to about 50–60 mg/kg of methylxanthines. The chocolate-coated dog treats in pet and vet shops are not real chocolate, just chocolate flavoured.

Symptoms start about 6-12 hours after the chocolate has been eaten and initially include bloating, increased water intake, vomiting, diarrhoea and restlessness, which can progress to severe agitation, tremors and collapse in some cases. Your vet will also find an increased heart rate, increased breathing and increased body temperature. The symptoms are basically due to excessive central nervous system stimulation.

Patients who die, do so because of heart failure, respiratory failure or organ failure due to hyperthermia. The theobromine starts breaking down after 17 hours and should be out of the system after three and a half days. The caffeine is much shorter acting and starts to break down after four and a half hours and should be out of the system within 24 hours.

Forcing the dog to vomit will only be effective soon after the chocolate has been eaten. It is unlikely to be effective after two to three hours, as the food has passed through the stomach by that time.

Activated charcoal powder can be dosed to absorb the stimulant chemicals and remove them via the faeces. As vets we often see more complications from owners forcing inappropriate mixtures into the dog to cause vomiting than symptoms from what the dog actually ate.

Strong salt solutions will cause vomiting, but can also cause severe salt imbalances and may cause brain dehydration. Some caustic solutions will cause severe damage to the oesophagus lining.

Extremely vigorous dosing will also often result in the solution being aspirated into the lungs.

When the solution contains soaps or salts this can severely disrupt the balance of the fluid keeping the lung alveoli open. Activated charcoal is inert and the lungs will not easily be able to reabsorb and remove it from the membranes.

Most dogs will eat chocolate and show no or only minor ill effects, so don’t panic. However, if the amount eaten is large, or the chocolate was the rich, dark variety, or if your dog has an underlying heart or seizure condition, it may be wise to seek the advice of a veterinarian sooner than later. The darker the chocolate, the more dangerous it is.

PS: Gemma still gets one or two chuckle balls every time a packet is opened. I just at least make her run for them.