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Permethrin poisoning in cats
Permethrin is an antiparasitic substance widely used in pipettes, collars and sprays intended for DOGS, as well as in certain insecticides for the home. It belongs to the pyrethroid family. Well tolerated by dogs, it is a nervous system poi...
What is it?
Permethrin is an antiparasitic substance widely used in pipettes, collars and sprays intended for DOGS, as well as in certain insecticides for the home. It belongs to the pyrethroid family.
Well tolerated by dogs, it is a nervous system poison in cats, whose liver cannot degrade it. A dog antiparasitic applied to a cat causes tremors and then severe convulsions, which can be fatal.
The error is common and almost always occurs in good faith: an “anti-flea” pipette purchased for the dog and used on the house cat.
Key point
Immediate life-threatening emergency. Permethrin-based dog antiparasitics cause severe seizures in cats and should never be applied to them.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Signs appear most often within a few hours of application or contact.
Muscular tremors, at first discreet, on the ears, face and back, then generalized.
Uncontrollable contractions and jerks, then real convulsions.
Staggering gait, cat losing balance, disoriented.
Profuse salivation, vomiting.
Agitation, startles at the slightest noise, hypersensitivity to touch.
High body temperature from convulsing.
Deep depression, then coma in the most serious forms.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Voluntary application of a pipette, spray or antiparasitic collar intended for dogs.
Use of an “anti-flea” product purchased outside the veterinary circuit, without verifying the target species.
Indirect contact: a cat sleeping next to a recently treated dog, licking it or rubbing against it.
Household insecticides, garden products or textile treatments containing pyrethroids, applied in a room accessible to the cat.
Home where a dog and a cat live together.
Purchasing pest control products in supermarkets or online without professional advice.
Packaging that looks similar from one species to another.
Reusing a leftover dog pipette “so as not to waste”.
Young, old or weakened cats, more sensitive.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
This is an immediate life-threatening emergency. Call a veterinarian immediately upon application, even before the slightest tremor appears.
Take the product packaging with you: the name of the substance and its concentration guide treatment.
Do not give human milk or medicine or try to make your cat vomit.
If the product has been applied to the skin, the veterinarian will tell you how to proceed; do not rub the coat vigorously yourself without warning, this may help the product to pass through.
At the clinic, the cat is washed with a suitable product and its temperature and nervous activity are closely monitored.
Treatment
The care is hospital-based.
The coat is decontaminated by careful washing in lukewarm water with a suitable degreasing product, often repeated.
Anticonvulsant and muscle relaxant medications control tremors and seizures; they are administered by the veterinarian, never at home.
An infusion, body temperature control and continuous monitoring accompany the treatment.
The duration of hospitalization depends on the persistence of nervous signs, sometimes several days.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
NEVER apply antiparasitic intended for dogs to a cat. Always read the species indicated on the box before any application.
Use products prescribed or recommended by a veterinarian, adapted to the weight and age of your cat.
In a household with a dog and a cat, separate the animals until the product dries completely and ask for advice on choosing a molecule that is safe for the cat.
Ventilate and keep the cat away after using household insecticides; respect the indicated time limits before letting him return to the room.
Discard leftover pipettes rather than reusing them on another animal.
Possible complications
Repeated and prolonged convulsive seizures, which damage the brain.
Dangerous rise in body temperature related to continued muscular activity.
Damage to the muscles and kidneys in prolonged forms.
Death in the absence of rapid treatment.
When to see a veterinarian
You have applied a product intended for dogs to your cat: call a veterinarian immediately, even if it appears normal.
Your cat trembles, jumps, or has muscle twitches.
He staggers, seems disoriented or has a seizure.
He drools a lot, vomits, hides and refuses all contact.
He slept against a recently treated dog and shows the slightest nervous sign.
Prognosis
A cat treated quickly, washed and stabilized before the convulsions become prolonged, most often recovers without after-effects.
The prognosis worsens when the attacks last, are repeated or the body temperature rises sharply.
The speed of calling the veterinarian is the determining factor.
Frequently asked questions
I applied the dog's pipette to my cat ten minutes ago: what should I do?
Call a veterinarian immediately, without waiting for the tremors to appear, and take the packaging away. Early decontamination of the coat, carried out in good conditions, completely changes the prognosis.
Can I use half a dog pipette on my cat?
No. It is not a question of quantity: the cat does not know how to break down this substance. No fraction of a dog pipette is acceptable on a cat.
My dog is treated against fleas, is my cat at risk?
Yes, by contact, especially if the two sleep together or lick each other. Tell the veterinarian that you also have a cat: there are molecules for dogs that are safe for the household cat.
How to recognize a dangerous product?
Look at the species indicated on the box and the active substance. Many dog products contain Permethrin. If in doubt, do not apply it and seek advice from a veterinarian or pharmacist.
References
AAFP — American Association of Feline Practitioners
ANSES — Agence nationale de sécurité sanitaire (France)
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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