Permethrin poisoning in cats

What is permethrin?

Permethrin is an insecticide. It’s a common ingredient in parasite prevention treatments for dogs. 

They work as neurotoxins by disrupting nerve function. Insects and parasites are highly susceptible to permethrin which is why it makes for such a useful insecticide.

So why is permethrin poisonous to cats?

In most species, permethrin molecules are broken down (metabolised) by their liver. A cat’s liver is not very well equipped to handle permethrin; they struggle to break it down and this is what causes the trouble.

Permethrin can be absorbed into the body from coming into contact with the skin, or by being ingested or swallowed. This means that a cat can be at risk even if they encounter a dog who has recently been treated with a permethrin-based product.

What are the symptoms of permethrin poisoning in cats?

Permethrin poisoning can be fatal to cats. Symptoms include severe muscle tremors and seizures. If you think your cat has ingested permethrin or if it has touched their skin, you will need to seek veterinary attention immediately.

The most common symptoms include:

• Muscle tremors
• Vomiting and diarrhoea
• Rapid heart rate
• Frequent twitching
• Seizures
• Excess saliva or drooling
• Fever
• Dilated pupils

What are the treatments for permethrin poisoning?

There is no antidote or direct cure for permethrin poisoning. Treatment consists of supportive care and medication to alleviate clinical signs. Inducing vomiting, if the poison has been ingested within 2 hours, is also useful. It’s therefore very important to contact your vet right away if you think your cat has been poisoned by permethrin.

The most common treatments for permethrin poisoning are:

• Decontamination: This will help cats if their skin has come into contact. Decontamination consists of bathing the cat in warm water. Using a mild detergent, the vet will remove as much of the product as possible to prevent further absorption through the skin.
• Induced vomiting: This will help if your cat has ingested the poison. This can also include gastric lavage (stomach pump) and the use of absorbent material such as charcoal to try to absorb the toxin from the intestines.
• Seizure & Tremor Control: The vet will administer treatment designed to reduce seizures and tremors. They may also use muscle relaxants, anaesthesia or heavy sedation to help your cat.
• Supportive Care: This may involve intravenous fluids, temperature readings and other forms of care. In severe cases, this treatment may have to continue for a few days. 
• Lipid Infusions: This can be helpful in extreme cases. The lipid may help to remove permethrin from inside your cat or to reduce the toxicity.

How do I keep my cat safe?

Stay alert. We recommend using parasite prevention treatments that your vet has prescribed, as opposed to supermarket or store-bought products. This way, you’ll know for a fact that you’re not only treating your cat with a safe product, you’re treating them with a product tailored to them and their needs.

If you do pick up an anti-parasite product from a shop, however, be sure to read the label thoroughly. DO NOT use dog anti-parasite treatments on your cat.

If you have a dog and a cat and use a permethrin-based solution on your dog, we recommend that you keep the animals apart for 72 hours after your dog has had their parasite treatment. Spot-on solutions are often so strong; a cat can become contaminated just by sleeping beside or coming too close to an animal that has been treated with it.

Need more advice on keeping your cat safe from permethrin poisoning?

For more information on permethrin and how to treat your cat against fleas effectively, contact your vet.

Find your nearest vet using our Find a Vet page, or speak to a vet online using Online Vets.