Spot-On Treatment Containing Amitraz Is Toxic to Cats

Products containing this active ingredient are meant only for dogs. Accidental exposure to cats is potentially very serious.

By: gnalnad
Contact your veterinarian if you suspect amitraz toxicity. By: gnalnad

Amitraz is an insecticidal ingredient contained in some canine products that kill ticks and demodectic mange mites.

It is the active ingredient in the topical wash Mitoban, the spot-on treatment ProMeris and the tick collar Preventic. So why, in an article about cats, am I talking about dogs?

Unfortunately, amitraz is toxic to cats and accidental contact with dog products containing this active ingredient is potentially very serious.

This can happen when people accidentally put a tick collar or a spot-on containing amitraz on their cat. Believe me, mistakes happen. All it takes is a lapse in concentration and…“Hey-ho! The cat is wearing the dog’s parasite treatment!”

As an example of how easy it is to make mistakes, my most recent case of this sort involved someone putting ProMeris in the dog’s food instead of on the skin. This resulted in a toxic dose of amitraz for the dog and an expensive trip to the vet.


Amitraz works on the same parts of the brain as certain veterinary sedatives. The symptoms are those of muscle weakness and drowsiness and if left untreated, there is a risk of coma and death.

Signs usually start about 2 to 6 hours after contact with amitraz. The cat becomes drowsy and may be difficult to rouse. His muscles become too weak to support him and if he tries to walk, he staggers or falls over.

Everything in his body slows down, from his heart rate to the contractions of his gut. His body temperature falls and becomes dangerously low. His bowel ceases to work; he may vomit or have diarrhea. If you see any of these signs contact your veterinarian, because if left untreated the cat may slip into a coma and die.


Amitraz is absorbed through the skin, as in the case of a tick collar put on a cat. It can also enter the body when a cat licks or chews a tick collar or if he licks a still-damp ProMeris spot-on applied to his dog buddy.

It is not fully understood why, but cats, along with the very young and small dogs, are especially sensitive to the effects of amitraz and just don’t mix.


A recent history of contact with a product containing amitraz and a previously healthy cat showing signs of sedation and wobbliness is sufficient to start emergency treatment.

While blood tests can be useful to rule out ill health, if the symptoms are severe most vets start therapy regardless of whether they have run blood screens or not.

Time is of the essence and once the antidote is given, many cats improve in less than half an hour. In terms of diagnostics, this is known as “diagnosis by successful treatment.”


If you accidentally put the wrong spot-on treatment on the cat, immediately wash it off with lots of running water. If you suspect your cat has amitraz toxicity, contact your veterinarian. In the early stages, it is a similar matter to give an antidote injection that rapidly blocks the action of amitraz in the nervous system.

If the cat licked or chewed a product containing amitraz, then doses of activated charcoal are given by mouth which help mop up any product remaining in his gut and prevent further absorption into the bloodstream.

If the cat develops sickness and diarrhea or his blood pressure is very low, then he may need intravenous fluids. A drip helps replace fluids lost through vomiting as well as supports his blood pressure and the circulation to his organs.


We all make mistakes. Always take a moment to read the packaging before you put a product on your cat. Most manufacturers make it very clear when a pet product is not safe for cats, so respect that warning and put it aside in favor of a cat-friendly alternative.


  • “Treatment of amitraz toxicosis.” Duncan, K. L. J Am. Vet Med Assoc, 203(8): 1115–1116.
  • “Toxicity and kinetics of amitraz in dogs.” Hugnet, Buronfoss & Pineau. Am J Vet Res, 57(10): 1506–1510.
  • Plumb Veterinary Drug Handbook. Donald Plumb. Publisher: PharmaVet. 9th edition.


This pet health content was written by a veterinarian.

Dr. Pippa Elliott, BVMS, MRCVS

View posts by Dr. Pippa Elliott, BVMS, MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty puggle called Poggle, 3 cats and a bearded dragon.

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