While some human medications can be used in pets, others can be very toxic. Unfortunately, it is often assumed that medications that can be bought over the counter for human treatment will also be safe for animals. Meaning that many animals are inadvertently poisoned by their well-meaning owners every year. 

Another common problem experienced is that where one human medication may be appropriate for use in dogs, that does not mean it is safe for cats or other animals. Importantly, even those that are safe to be given to pets must be accurately dosed to avoid potentially severe side effects. Before attempting to treat your pet at home, always seek advice from your vet. 

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Here are some of the most common myths, questions and half-truths surrounding the use of human medications in animals.

True or False…

All human medications are different to animal medications – FALSE

Some medications prescribed by your vet are also human medications, the same as would be prescribed by your doctor. However, this is not always the case. 

Some medications used in animals contain the same active ingredient as medications used for human treatment. However, the human medicine formulations may contain xylitol (an artificial sweetener) or other ingredients that are toxic to pets, even if the active ingredient itself can be safely used in animals. It is important that you do not medicate your pet with your own medication even if it is the same active ingredient.

Paracetamol is dangerous to use for my pet – DEPENDS

Paracetamol is commonly found in most homes and can be bought without a prescription, including formulations for children.  

In certain circumstances, it can be used by veterinary surgeons as a painkiller or to treat fever in dogs. Importantly, the dose for dogs is different to that in humans. Potentially fatal side effects (including liver failure) can be seen in dogs if they are given an excessively high dose or if they have underlying liver problems. In addition, certain human paracetamol formulations contain artificial sweeteners, some of which are toxic to dogs. Consult with your vet before giving paracetamol to your pet. 

Paracetamol should never be given to cats. They are unable to metabolise paracetamol meaning that it builds up in their body. This has effects on their red blood cells meaning that they are less efficient at carrying oxygen and can result in liver or kidney failure which can be rapidly fatal. 

Ibuprofen is dangerous for my pet – TRUE

Ibuprofen is a commonly available painkiller and anti-inflammatory that most people have in their medicine cabinet. Importantly, dogs and cats metabolise ibuprofen differently to humans and even a single tablet given to a 20kg dog can cause signs of toxicity. Potential side effects include vomiting, bleeding from the gastro-intestinal tract (which can result in perforation), kidney failure and, in severe cases, seizures and coma. For this reason, ibuprofen should never be given to pets. 

Aspirin is dangerous for my pet – DEPENDS

Aspirin is not used by vets as a first-line pain relief as there are more effective painkillers with fewer side effects available for your pets. Potential side effects include anaemia, liver or kidney problems, stomach or gastro-intestinal bleeding. 

That being said, low doses of aspirin are sometimes used by vets in animals who are at an increased risk of forming blood clots (for example patients with certain heart or kidney conditions). However, these are very particular situations and its safe use is dependent on many factors. 

Vet medicines cost the same as human medicines, but vets increase the price – FALSE

Unfortunately, veterinary specific versions of medicines tend to be more expensive than the human equivalent. This is due to various economic and development costs associated with producing products for smaller markets. Human medications benefit from an economy of scale of production. Even in the UK there are 8.5 million dogs and 11 million cats compared with 68 million people. People in the UK benefit also from prescription medications being subsidised by the NHS.

Vets can prescribe human medications for pets but choose not to – FALSE

Veterinary surgeons must prescribe medications for their patients according to ‘The Prescription Cascade’. Certain medications used by vets do not have an animal equivalent, and in these circumstances, vets routinely use the human variety of the medication. However, if an animal medication is available, vets must legally dispense this for their patients. Human medications can only legally be used if there is no suitable animal equivalent of the medication available. It is an offence to prescribe a human medication instead of animal medication purely for cost reasons.

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