Antifreeze: A Deadly Poison to Our Pets

If you think your pet may have been poisoned contact:
Animal Poison Control Center: 1-888-426-4435

Fall is a busy time of year for everyone. You’re getting kids back to school, trying to finish those summer projects, and getting the car ready for winter. This time of year we get concerned about one of the most serious poisonings that we see in dogs and cats….ANTIFREEZE.

Antifreeze is essential to keeping your car running during the winter. Many people have an old jug of it lying around in the garage or basement. Many people’s cars may also develop a leak in the radiator over the course of the winter and there may actually be antifreeze on the driveway or garage floor.

The active ingredient in most antifreezes is called ethylene glycol. This works as antifreeze because it lowers the temperature at which water freezes. Unfortunately, ethylene glycol has a sweet flavor and is often consumed by cats and dogs (and even children).

Ethylene glycol is extremely toxic. Initially ethylene glycol causes similar symptoms to alcohol ingestion such as depression, weakness, and difficulty walking. In short they may act drunk for several hours. This generally resolves within several hours and the pet may appear fine. However, ethylene glycol causes massive and severe damage to the kidneys and within 1-3 days kidney failure occurs.

Kidney failure caused by ethylene glycol toxicity is severe and progresses rapidly. Symptoms seen often include lethargy, loss of appetite, vomiting, increased thirst and urination. These symptoms develop rapidly because the ethylene glycol and its breakdown products essentially kill the kidneys. By the time these symptoms are present treatment becomes much more difficult and many animals will die despite treatment.

Because ethylene glycol toxicity is so severe and often fatal the best treatment is prevention. Do not store antifreeze in your house or garage where pets or children may have access. Make sure that there is no antifreeze leaking from your car. If there are any spills of antifreeze clean them up IMMEDIATELY.

My Pet May Have Consumed Antifreeze….What should I do?
If you think that your pet may have consumed or had exposure to antifreeze contact your veterinarian IMMEDIATELY. If this occurs when your veterinarian is closed you should contact a 24 hour emergency facility (these have become common all over the country and usually there is at least one just a short drive away).

Some antifreezes are so-called “Safe” antifreezes. These generally contain propylene glycol instead of ethylene glycol. While these are less toxic than the ethylene glycol antifreezes they can still cause significant harm and you should contact a veterinarian immediately if your pet ingests them.

Rapid treatment of antifreeze poisoning is essential. If the poisoning is treated before the ethylene glycol has a chance to damage the kidneys, most pets will do well and have no long term effects.

However, once kidney damage begins occurring it may be too late.
Treatment of ethylene glycol toxicity involves inhibiting the alcohol dehydrogenase enzyme (the enzyme that breaks down alcohol). Alcohol dehydrogenase breaks ethylene glycol down into more toxic components which attack the kidneys. By blocking the breakdown of ethylene glycol into its more toxic byproducts it is less likely to cause damage to the kidneys and it is slowly excrete from the body.

There are 2 medications available for the treatment of ethylene glycol.

1. The original treatment is the intravenous administration of alcohol (ethanol). Essentially, the patient is made drunk. The alcohol fills up all of the alcohol dehydrogenase enzyme sites and the ethylene glycol cannot be converted to its toxic components and is excreted. While this treatment can be effective it is not ideal. As most people are aware alcohol has a number of serious side effects, in most cases it must be administered for at least 24 hours. Do not attempt this treatment at home.

2. A newer medication is called Fomepizole (also known as 4-MP or Antizol). This is the preferred treatment of ethylene glycol toxicity. It blocks the alcohol dehydrogenase enzyme without producing the serious side effects of ethanol.

Most pets will also receive IV fluid therapy as part of their treatment. Hemodialysis is also an effective treatment but this treatment is limited to universities and is expensive.

Remember, antifreeze can be deadly. Use care if you are using it. Make sure you immediately clean any spills and discard any unused antifreeze (contact your town for proper disposal practices). If you have any concerns that your pet has been exposed to antifreeze call your veterinarian immediately. If treatment occurs within 8 hours of ingestion the prognosis is usually good. After 8 hours the prognosis rapidly declines and many pets will die or have permanent kidney damage.

If you think your pet may have been poisoned contact:
Animal Poison Control Center: 1-888-426-4435