Permethrin and pyrethrum are insecticides that help control parasites, such as fleas and ticks. Sadly, there have been many instances of permethrin poisoning in cats, often by cat owners who have unintentionally poisoned their cat by applying their dog’s spot-on flea treatment.
Unlike dogs, cats lack the enzyme needed to detox products containing permethrin or pyrethrum. Even tiny doses can quickly result in permethrin toxicity, causing serious illness or death. Tick and flea treatments for dogs are highly concentrated and should NEVER be used on cats.
Why are Cats at Risk?
Cats’ unique feline physiology means that they can’t break down permethrin. This makes a tiny dose potentially toxic, turning a ‘medicine’ into a poison. Feline livers lack a crucial liver enzyme, called hepatic glucuronosyltransferase. Permethrin is broken down by the liver, so a little permethrin hangs around for a long time. To make matters worse, permethrin is fat soluble, and it can be absorbed through the skin. A cat who rubs against a treated dog can be poisoned without having the toxic flea product directly applied to their skin.
Permethrin toxicity isn’t the same for dogs and cats, which is why you’ll find flea collars or spot-on flea treatment for dogs containing permethrin in pet stores. These products are widely available and owners are often unaware of the toxicity risk for cats.
How are Cats Poisoned?
Sadly, the number one way that cats are poisoned, is when their owner doesn’t realise the danger and applies a dose of permethrin flea treatment intended for dogs to their cat. Poisoning can also occur when a cat bunts against a dog’s coat that’s wet with permethrin flea treatment. This affectionate act contaminates their own fur, and the permethrin is absorbed through the skin or when the cat grooms itself. A cat can also be poisoned when they lay in the dog’s bed or sit on the same furniture.
There are some feline flea powders on the market and you can purchase cat collars impregnated with permethrin. The dose in cat collars is low, which means the risk is low… but the risk is still there. For this reason, trusted and respected organisations such as International Cat Care advise against using any flea products that contain permethrin, especially since more effective and safer products are available. They have also started a campaign to raise awareness of the dangers of permethrin poisoning for cats.
Symptoms of Permethrin Poisoning
What are the signs of flea product toxicity, and what should you watch out for?
The speed of onset and severity of poisoning symptoms tends to vary dependent on the dose given and the concentration of the toxic ingredients. When exposed to small quantities, it can take up to three days for signs to appear. Flea product toxicity can also occur much more quickly, from one to 12 hours after application. The first clue is likely to be the cat seeming unsettled, restless, anxious, and staggering as if drunk. Other signs include muscle twitches and tremors, and alarmingly – seizures.
Be alert for:
- Twitching whiskers
- Muscular tremors
- Heavy salivation
- Poor co-ordination such as staggering and stumbling
- Dilated pupils (these appear extra black and round, and don’t narrow down in bright light)
- A raised temper (due to the extra muscular activity)
Immediate Action for Flea Product (Permethrin) Toxicity
If you think your cat has come into contact with a flea product containing permethrin (either directly or indirectly through a treated dog) contact your vet IMMEDIATELY. There is no antidote, but acting quickly can save your cat’s life.
The first step, which you can do at home, is to decontaminate the cat’s coat as quickly as possible to minimise the damage. Wash the cat in a bath of lukewarm water with diluted dishwashing liquid such as Dawn®. Doing this helps reduce the amount of permethrin absorbed through the skin and can be the difference between life and death. After bathing, dry the cat throughly and keep them warm, then go to your closest veterinary emergency clinic.
Veterinary Treatment of Permethrin Poisoning in Cats
Veterinary treatment will depend on how badly affected the cat is by the toxic flea product but options for supporting cats with signs of permethrin poisoning are:
Intravenous (IV) fluids
This has several benefits. For example, most cats are too poorly to eat or drink, so fluids prevent dehydration which in turn protects the kidneys from shutting down. Permethrin is fat soluble, so it take a while to flush out of the body, but intravenous fluids help encourage this.
Muscular tremors and seizures are exhausting and dangerous. A range of different medications may be necessary to promote muscle relaxation and limit the effect of seizures. In the most severely affected feline patients, general anaesthesia and insertion of a breathing tube may be necessary, to try to bring things under control.
Muscle contraction generates heat, and in turn a high fever can be dangerous. Nursing care includes monitoring the cat’s temperature and keeping the cat cool. Also, cats that are too weak to stand, need to be turned over regularly to prevent bed sores.
The latest innovation in the treatment of permethrin toxicity is the use of lipid infusions. These draw the permethrin out of the body fat and into the blood stream for the kidneys to get rid of in urine. This seems to help in the worst cases, but this treatment is in its infancy and not widely available.
The majority of cats will make a full recovery if they are treated promptly by a veterinarian. The prognosis for more severely poisoned cats, and especially those experiencing seizures which are harder to control is not so promising. Sadly, statistics show that around 10-40% of cats with permethrin poisoning simply don’t survive, even with veterinary treatment.
Preventing Permethrin Toxicity in Cats
Prevention in this case is definitely better than cure. So, how can you keep your cat safe?
Quite simply, DON’T USE permethrin products on your pets or around the house.
- Avoid all pyrethrum-based (pyrethrin, permethrin or pyrethroid) flea control products to minimise the risk of toxicity.
- You should NEVER apply a dog flea product to a cat.
- If have dogs and cats in your home, reduce the risk by choosing a permethrin-free flea treatment for your dog. It’s also a good idea to separate the dog from the cat until any topical flea treatment is dry.
- Always make sure you read the active ingredients and warning labels on the packet. This includes when you’re shopping online – make sure you know what the active ingredients are and opt for a permethrin-free product.
- If you’re picking up a flea treatment off-the-shelf in store, buy a species specific product suitable for the cat’s weight and age. Kittens can be much more sensitive to flea treatments than adult cats, so it’s important to use the correct dose for their age.
- Double-check the packaging and product before you use it. It can be easy to pick up the wrong packet in store, e.g. when cat and dog flea treatments are stored side-by-side and the packaging looks similar, or you’re in a rush.
- If you’re in doubt about the best flea treatment product to use, talk to your vet and seek their advice.
- Read the ingredients of garden pest products before using around your home or garden. Fly sprays or ant sands often contain permethrin or other pyrethroids making them unsafe for cats.
Finally, there really is no need for pyrethrum-based flea products for dogs or cats. There are much more effective and SAFER treatments available.