permethrin poisoning in cats with fleas

Bob Martin to Tackle Permethrin Poisoning in Cats

Pet health company, Bob Martin, has taken action to remove their permethrin-based flea treatments from general sale to reduce the misuse of these products.

Permethrin based flea treatments are widely available, but strictly for canine use only as they are toxic to cats. However, through mistake or misunderstanding these products are still occasionally used on cats. As a result permethrin poisoning is currently the most commonly reported cause of feline poisoning worldwide.

Prevent permethrin poisoningBob Martin has already voluntarily removed permethrin from their ‘Spot-On’ range, using the less toxic fipronil as the flea-killing, active ingredient. This next move is a big step forward in reducing the risk of permethrin poisoning. Their fipronil products are available for dogs and cats.

The products will still be available through retail pharmacies, where qualified pharmacy staff will be able to advise consumers about the use of the product. The company is also pushing for the Veterinary Medicines Directorate to change permethrin licensing, so that all products containing this pesticide may only be purchased if advice is given on their safe use. Based on previous permethrin toxicity studies, more than 50% of owners purchase permethrin products where no guidance or advice is currently provided with the sale 1.

Bob Martin is rolling out a new ‘Clear’ range of flea collars containing a natural extract from the neem tree seed, margosa extract. This natural repellent will ensure customers are still able to purchase flea repellents from general retail stores.

Permethrin Poisoning in Cats

Permethrin is an effective pesticide used for the removal of fleas. It can be used safely on most mammals, however, it poses a toxic risk to cats. Cats are unable to metabolise the compound effectively after absorption though the skin, where it is able to interfere with the nervous system.

Although the exact lethal dose of permethrin is unknown for felines, a dose of 100mg/kg is considered lethal 2. Canine permethrin flea treatments can be highly concentrated, which means that a number of these products can contain a lethal dose in a single application if used on a cat. There is also a risk of permethrin poisoning for cats that come in to close contact with treated dogs.

In the UK, over an 18 year period, the Veterinary Poisons Information Service received 1,306 enquiries regarding exposure to permethrin. Of these enquires, over 500 concerned the use of permethrin flea products on cats 3.

Such a high incidence of toxicity indicates that there currently isn’t enough being done at the point of sale to highlight the potentially lethal consequences of permethrin misuse.

Symptoms of Permethrin Poisoning in Cats

Symptoms of permethrin poisoning can become apparent immediately but may take up to 72 hours to manifest. Muscle tremors and twitching are the most commonly observed symptom, but ingestion of permethrin through grooming can cause hyper-salivation and vomiting. More severe cases of poisoning can result in:

  • Tremors
  • Seizures
  • Fever
  • Increased heart rate
  • Disorientation
  • Hyperthermia
  • Temporary blindness

Treating Permethrin Poisoning

Decontaminate the affected area – this can be done at home, by using lukewarm water (neither warm nor cold, as this can increase the absorption/toxicity of permethrin) and shampoo/mild detergent to remove any permethrin that has not yet been absorbed through the skin. Dry the area after cleansing.

Managing Symptoms – a veterinarian can administer muscle relaxants or sedatives to control the tremors or seizures that may be present.

Supportive Therapy supportive care provided by a veterinarian or nurse includes maintenance of body temperature and providing intravenous fluids. The patient may also be intubated to facilitate breathing.

Intravenous Lipid Administration Although still requiring further research, IV administration of a lipid emulsion has had some promising results in cases of permethrin poisoning 4. The mechanism by which the IV lipid emulsion works is not yet known, but speculation is that it is able to draw the toxin out from the nervous system.

Prognosis Following Permethrin Poisoning in Cats

In cases of mild poisoning, the outlook is typically good. In more severe cases, the outcome depends upon the speed of treatment. One study suggested that 1 in 5 of reported cases resulted in a fatality 5.

The main danger of permethrin toxicity is the outcome of the seizures that occur as a result of poisoning. These seizures can be severe if not treated, resulting in brain damage. Long lasting seizure activity can also cause kidney failure.

If treatment goes well, the patient can recover as soon as 2-3 days after exposure without any long term effects as a result of the toxin.

Image Credit – Erica Hampton


  1. Malik, Richard, et al. “Permethrin spot-on intoxication of cats: Literature review and survey of veterinary practitioners in Australia.” Journal of Feline Medicine & Surgery 12.1 (2010): 5-14.
  2. Hansen, Steven R., et al. “Pyrethrins and pyrethroids in dogs and cats.” The Compendium on continuing education for the practicing veterinarian (USA) (1994).
  3. Boland, Lara A., and John M. Angles. “Feline permethrin toxicity: retrospective study of 42 cases.” Journal of Feline Medicine & Surgery 12.2 (2010): 61-71.
  4. Brückner, M., and C. S. Schwedes. “Successful treatment of permethrin toxicosis in two cats with an intravenous lipid administration.” Tierärztliche Praxis Kleintiere 2.2012 (2012).
  5. Malik, Richard, et al. “Permethrin spot-on intoxication of cats: Literature review and survey of veterinary practitioners in Australia.” Journal of Feline Medicine & Surgery 12.1 (2010): 5-14.

About James Watts

BSc Bioveterinary Science. Editor of PetSci. When I'm not writing, learning, discussing, or reading about animals, you know it's the weekend! Currently developing PetSci HealthTrak, the fast and easy way to monitor your pet's weight and calorie intake. HealthTrak offers a simple way to track your pet's progress, helping them achieve a healthy weight and a long, happy life.

Check Also

Two dog owners and their dog

Pet Ownership Soars Amidst Pandemic

A number of population surveys have indicated a rise in pet ownership over the last …

Minitablets for Cats Set to Make Medicating Easier

Minitablets for cats could improve the compliance of feline patients in the future. All cat …


  1. Alexandra Maldwyn-Davies

    Hi James,

    I have ten cats and three dogs. When it came to doing their monthly flea treatment yesterday, I put Advantix for dogs one of my beloved cats, Steve. I’ve recently opened a charity shop for animals, my mum has moved in with me… and I think it was all a bit too much. Too much to do, not concentrating enough. I am absolutely devestated beyond belief. I cannot believe my stupidity and the guilt I’m feeling is just awful. I’m always so careful with these things. I pride myself on how I care for my animals (all rescued) and feel so dreadful for having put him through this. He’s currently in intensive care with my vet. He’s on a drip and been put in an induced coma. He’s fighting for his little life. He was no better, no worse this morning. He’s still having convulsions. I’ve been trawling the Internet all night and day and found out about lipid infusion. It works alongside the regular treatment and has had some very positive feedback. At this stage, anything is worth a try. It has taken all day to get hold of it, but I finally managed to order some from an emergency hospital pharmacy. The vet had never heard of it, but agreed to give it a go. He’s having it now. I’ll go back down and see him again in a couple of hours. I love him so much. He’s really fighting to survive. Is there anything else I can be doing?

    • Hi Alexandra, I am so sorry to hear this. This is exactly why companies need to seriously consider the use of permethrin in flea treatments. It’s also why this first step by Bob Martin is definitely one that is long overdue.

      Did you read this article on lipid infusion? Brückner, M., and C. S. Schwedes. “Successful treatment of permethrin toxicosis in two cats with an intravenous lipid administration.” Tierärztliche Praxis Kleintiere 2.2012 (2012).

      I think at the moment, there is not much more you can do. Your vet will be offering all the supportive care they can. I hope Steve pulls through this and am wishing you both the best.


  2. An employee used a permethrin product on his 12 month old cat…ALL the signs and symptoms you describe(short of loss of consciousness) were shown…but the cat began to drink and eat, the next day. The local Vet insisted on admitting the cat for 24 hours(on the THIRD DAY!) and doing a ‘blood test’. They gave him a price of £350.00.
    I did a deep web search…the cat had survived over two days and was improving…I telephoned another practice and they said, as you write, “SUPPORTIVE CARE…warmth, IV fluids if dehydrated and an anti-convulsive if still fitting today…BUT there is little else that is possible. 10%(you mention ‘one in five) may not recover. it is highly promising that this cat is eating and drinking on the third day”. I urged my employee to collect the cat from the practice and to STOP any blood tests! He tried, but they convinced him to leave the cat with them until tonight. They agreed NOT to do the ‘blood tests’ and they would, consider anti-convulsives. They said, “We will TRY to keep the cost down”!!! I wish he had read your superb article FIRST and had discussed the problem with me…we could have done a web search in 10 mins and saved him £350. I am used to dealing with humans…BUT it is appalling that people do not read instructions and that there are so many instances of dog products being used on cats. Packaging should HIGHLIGHT the hazard, much as for that on cigarettes. “This product may kill cats”!

  3. Would the cats eyes be affected, one pupil wide but the other small?
    I took a lost/stray kitten to my local vet after I found her with the symptoms you listed & her eyes were so different from each other.
    She had been hanging around for several days & we fed her & she was very hungry & dirty. She was happy & my son gave her lots of cuddles. We took her to vets & she was chipped but no address shown! So brought her back home until vets could chase up her microchip issues. We have two cats already & they were not impressed so had to leave her outside(we gave her food/water/bed& blanket) but two days later saw her outside very distressed & had tremors & couldn’t move properly & she was salivating a lot then I noticed her eyes were not how they should be or how they was the day before. We took her back to a diff vets & he said he will do bloods & that it could be toxi posioning . Poor little kitten looked so poorly

  4. My cat has just been rushed to the vet because of Bob Martin carpet flea spray. We used it and locked up room with plenty of ventilation. 24 hours later (twice that which BM recommends) the cat went in and became incredibly ill.
    Permethrin is still the active ingredient in their carpet spray. The vet told us to never use Bob Martin products ever again.

  5. I am not sure exactly what is going on with my Persian cat Tekela who is 7 years of age.I lost Bailey just 2 weeks ago who was Tekela uncle Tekela ha lost weight I have taken him to my vet as I have been very concerned.But about 3 weeks ago I used Bob Marin clear on Tekela a spray for fleas ticks and home I have never used it before.
    I was wondering if this Bob Martin product has made my Tekela lose weight? I asked my vet he informed me that Tekela was upset because Bailey had died and has given him the treatment needed.But I am not so sure.All of this has coincided with my beloved Bailey dying.He was 13 when he died.
    Can somebody please inform me or advise me if it is the Bob Martin product that has done this to Tekela.Although I have now thrown the product away and only use stronghold.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.