Caffeine and coffee: toxic to animals

Why is caffeine dangerous for animals?

Caffeine belongs to the methylxanthines, a group of chemical substances that occur naturally in coffee beans, tea leaves and cocoa plants. In humans, caffeine has a mild stimulating effect, but in dogs and cats it acts as a powerful overstimulation of the central nervous system, the heart and the kidneys. The substance blocks adenosine receptors, causing the normal inhibitory function of the nervous system to fail and the body to enter a state of overactivation [1].

Cats are generally more sensitive than dogs, but for both species the following applies: small amounts can already be dangerous, especially for small or young animals. Dogs and cats break down caffeine much more slowly than humans, causing the substance to act longer and more intensely.

Sources of caffeine

Caffeine appears in more products than many people think:

• Coffee and espresso — including coffee grounds, used pods and empty cups
• Tea — black, green and white
• Energy drinks and sports drinks
• Pre-workout supplements
• Caffeine tablets and some headache medications
• Chocolate — contains the closely related methylxanthine theobromine, which has the same mechanism [3]

Note: residues in discarded packaging or empty cups are just as dangerous as fresh products.

Symptoms of poisoning

Symptoms usually occur within one to two hours after ingestion [1]:

What to do in case of (suspected) poisoning?

Do not wait for worsening. Contact your veterinary surgeon or the nearest veterinary clinic immediately as soon as you suspect your animal has ingested caffeine — even if your animal still looks normal.

• Bring packaging or residues so the veterinary surgeon knows what was ingested and how much
• Induction of vomiting is only useful within a limited time window and must only be performed by a veterinary surgeon
• There is no specific antidote; treatment is symptomatic (induction of vomiting, activated charcoal, antiepileptics, cardiac rhythm monitoring) [1][2]
• In cases of severe poisoning, haemodiafiltration can be used to actively remove caffeine from the blood [2]

The prognosis is good with rapid intervention. However, delayed treatment or very high doses can be fatal [1].

'Natural' does not mean 'safe'

Coffee and tea are often seen as everyday, harmless products. But what is normal for humans can be life-threatening for animals. Never give your pet products containing caffeine — not even as a small taste or leftover. Store caffeine-containing supplements and medications out of reach of animals, just like energy drinks and chocolate.