Q) Is There An Antidote For Antifreeze Poisoning?

If your pet has ingested antifreeze, it is an emergency and you need to get help right away. Don’t waste any time, and call your nearest animal emergency hospital immediately. This is a time-sensitive matter and the clock is ticking. Antifreeze poisoning is an emergency. Call your nearest emergency vet STAT. Every minute counts.

On today's episode of Twin Trees Vet Talk, we welcome our special guest and mentor, Dr. Trevor Enberg. Dr. Enberg is a Veterinary Emergency and Critical Care Specialist at Canada West Veterinary Specialists in Vancouver, BC. Dr. Enberg helps us answer the question:

Q) Hello. I have been reading multiple stories and articles about dogs accidentally drinking anti freeze this time of year. Is this a rare thing or do you see this often? I read that there is an antidote, just wondering if you carry said antidote on site or if it is something that is not easily accessible? Thank you for you time.

Antifreeze is a bright green liquid that is poured into the radiator of a car to keep the engine from freezing in the winter. It is also called “engine coolant,” because it conveniently prevents the radiator fluid from boiling in the summer.

The toxic ingredient in antifreeze is called ethylene glycol. The compound is similar to alcohol, but it has a sweet taste that is appealing to animals. When ethylene glycol is metabolized by the body, toxic byproducts (oxalic acid, etc.) are released. Some regions now require that a bittering agent be added to antifreeze to reduce the risk of accidental ingestion by animals and children.

It is a bright green liquid that can be found in most garages. Less than a tablespoon can be fatal to a small dog or cat.

Many people keep antifreeze in the garage. Although antifreeze poisoning is often thought of as a cold-weather problem, dogs and cats can become poisoned with antifreeze at any time during the year. Less than a tablespoon can be fatal to a small dog or cat.

There is an antidote for antifreeze poisoning (fomepizole or 4-mp is the first line antidote; ethanol is a second line antidote), but it must be administered within a critical amount of time (less then 3 hours in cats; less than 8-12 hours in dogs). The sooner the better (ideally within 1 hour of ingestion), as outcomes worsen with every passing hour. After this timeframe, the poisoning is almost always fatal without hemodialysis.

Hemodialysis (which involves filtration of the blood) help filter the toxin out of the blood and is becoming the standard of care in referral hospitals. Hemodialysis is typically very expensive and requires access to a veterinary emergency and critical care hospital.

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    The signs of ethylene glycol poisoning occur in 3 stages:

    Stage 1 (30 min- 12 hours): “Drunkenness,” drooling, seizures, excessive thirst and vomiting.

    Stage 2 (12 hours – 24 hours): The signs seem to temporarily improve. This can be very misleading! Continued harm is occurring to the body.

    Stage 3 (12-24 hours in cats; 36-72 hours in dogs): These individuals begin to look very, very sick. You may notice profound lethargy, loss of appetite, drooling, vomiting, seizures and an abnormal smell to the breath. At this stage, KIDNEY FAILURE leading coma and death can occur.

    How Antifreeze Poisoning Happens:

    Antifreeze is a deadly household item. It leads to kidney failure and death if ingested. Antifreeze (Engine Coolant) is one of the most dangerous household substances for dogs and cats. It is also toxic to people. In fact, thousands of people are treated for this type of poisoning every year in North America. It is important to recognize this substance so that you can to protect your pet.

    The toxic ingredient in antifreeze is called ethylene glycol. Antifreeze/engine coolant contains 95% ethylene glycol. Although antifreeze is the most common source of poisoning, ethylene glycol can also be found in motor oils, brake fluid, windshield deicing agents, paints, wood stains, solvents and developing solutions used in photography. It is also used in the manufacturing of polyester.

    Pets can become exposed by drinking antifreeze that has leaked out (or been drained from) of vehicles or by drinking other ethylene glycol-containing substances (wood stains, etc.)  that have been improperly stored. Antifreeze is sometimes put in the toilets and water pipes in vacation homes and cottages to prevent the pipes from freezing in the winter while nobody is home. I know of dogs that have been poisoned in these situations from drinking toilet water that contained antifreeze.

    How to prevent antifreeze poisoning:

    It is important store antifreeze out of the reach of pets and children and to be extremely careful when using this product at home.

    Do not allow the used antifreeze to drain onto the ground when draining it from your vehicle. Instead, collect it into a child-proof container and LABEL the container, tape the lid to prevent easy opening, and store it safely until it can be recycled. (I know of one person who drank antifreeze that had been drained into a Gatorade bottle and left in the backseat of a car.)

    Store this and all chemicals out of the reach of pets and children.

    Antifreeze that has circulated through an engine contains other toxins as well (heavy metals such as lead, cadmium and chromium), making it very toxic to the environment, wildlife and ground water.

    Used antifreeze and containers can be easily recycled in most places because it can be passed through a filtration system and re-used. Your local mechanic can help. In BC, you can find your nearest recycling station using this easy tool called “The Recyclepedia.”

    Used antifreeze contains poisons and heavy metals. It should be collected, labeled, and recycled (ask your mechanic).

    Ethylene glycol used at airports (for the deicing of aircraft and runways) is a major source of environmental contamination, as it leaches into the land and nearby water supply. Ethylene glycol from aircraft and runway de-icing results in environmental pollution.


    1) DON'T WAIT TOO LONG TO GET HELP! If you wait too long, it could be too late. This is especially true for concerns such as laboured breathing, pale gums and weakness. You know your pet best, so if you are worried or concerned, "when in doubt, check it out!"

    2) PREVENT THE PREVENTABLE. Learn as much as possible about dangers that face your pet, such as household poisons, seemingly harmless objects (like toys, clothing, garbage and rocks), other animals, and vehicles. Pets are like toddlers and they need a responsible adult/babysitter to protect them from danger. Puppies and kittens need to start their vaccines at ~8 WEEKS (and they need boosters too!) to protect them from deadly diseases.

    3) BE PREPARED FOR THE WORST CASE SCENARIO. Have a plan in place, know your nearest emergency clinic, have the ASPCA phone number on speed dial. Know basic first aid training and CPR. But MOST IMPORTANTLY, BE FINANCIALLY PREPARED. The cost of medical treatment in an emergency, and the owners' ability to pay for it, is probably the most important factor that determines whether a pet will receive the medical care it needs. The best way to protect yourself is to have good medical insurance for your pet. Do your research.

    **REMEMBER**: WE ARE ALL ON THE SAME TEAM, with the best interest of the patient as everyone's first priority. Let your vet do what he/she does best, and don't try to grab the steering wheel and obstruct your vet from doing his/her job. We are all in the same car, we are all headed to the same place, but only one of us has the driver's license (meaning, only the vet has the medical training and background to "drive the car"). 


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