Ticks are parasites that carry diseases — in other words, they are a serious health risk to any dog.
However, you need to be careful when protecting your dog against ticks because some products are toxic to them and, if used incorrectly, can make your dog ill.
Many common anti-tick products, such as collars, shampoos and dips, contain amitraz. That chemical is designed for use on the dog’s coat or skin, and if the dog accidentally licks or eats a product containing amitraz, he may become ill.
Products containing amitraz — Preventic is one such brand — are safe when used correctly, but if the unforeseen happens and your dog chews his tick collar, seek prompt veterinary advice.
Small and elderly dogs are more sensitive to the toxic effects.
Taking the scenario where a dog swallows his tick collar, signs of ill effects take 2 to 6 hours to present. Amitraz affects most body systems including the gut, heart, respiratory system and brain.
Symptoms of amitraz poisoning include:
- Dilated pupils
- Heavy salivation
- A dull mental state or sedation
As the heart rate drops and blood pressure falls, a dog’s vital signs are impaired. Eventually, if enough amitraz was ingested and the dog is not treated, he may have seizures and die from heart and respiratory failure.
Be careful with treatments for cats, too. This video shows the side effects cats can have from amitraz (the cat recovered fully):
Amitraz is an external treatment and not meant to be eaten or swallowed. If ingested, it is absorbed across the stomach lining and enters the bloodstream.
Once there, it works against the central nervous system and inhibits many of the messages it sends. This has a broad sweeping effect on most of the body systems. For instance, it causes the heart rate to drop, blood pressure to fall and the animal to lose heat and become hypothermic.
Amitraz also removes nerve stimulation from the gut, which in effect goes to sleep and stops working. This leads to sickness, diarrhea and sometimes a buildup of gas that gives the dog a bloated appearance. It also inhibits insulin release, and the dog’s blood sugar level rises, sometimes to toxic levels.
This is often made by a combination of history and clinical signs. A blood test is available to measure amitraz levels in the blood, but it is rarely used because treatment must be immediate, and the test results take too long to come back.
A “smoking gun” history is if the dog has recently been bathed in amitraz, or the dog’s tick collar has gone missing. If the dog is also showing dilated pupils and heavy salivation, this is usually enough proof to start treatment.
If the dog swallowed a collar, then taking radiographs to check if the collar is in the stomach is advisable. If the collar is still in the stomach, this influences the treatment path.
To reduce further exposure, wash the dog with warm soapy water, removing any lingering residue.
Again, with the collar scenario, if the dog ate it within the past 2 hours and is not showing signs, then the veterinarian may use a drug to make the dog sick and bring the collar back up. Surgical removal of the collar via laparotomy may be necessary; otherwise, the collar will constantly release amitraz.
After the dog has eaten amitraz, active charcoal given by mouth every 4 hours can help mop up any drug still sloshing around in the gut. Your veterinarian may use drugs, such as yohimbine or atipamezole, to counteract the neurological effects of the amitraz.
These dogs are often hypothermic (their body temperature is low) — so keeping them warm is an important part of treatment. Also, intravenous fluids to support their circulation and diluted high blood glucose help stabilize the dog.
If treatment is given promptly, most cases recover. Dogs who do not do as well are those with serious clinical signs at the time of presentation to the vet.
- When you’re using a tick collar containing amitraz, always trim away any excess length so the dog cannot chew it.
- If you’re using an amitraz wash or shampoo, follow the directions closely as to how to dilute and use the product, and never let the dog lick his wet coat or drink the rinse water.
- Handbook of Small Animal Toxicology and Poisonings. Gfeller & Messonnier. Publisher: Mosby
- “Insecticides and molluscicides.” Gwaltney-Brant. Clinical Veterinary Toxicology. Publisher: Mosby.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 17, 2018.