All Pets Veterinary Clinic
Dogs and cats commonly become poisoned by antifreeze. Because antifreeze has a sweet
taste, animals will often drink it readily. The remainder of this article will focus
on the signs, diagnosis, treatment, prognosis, and prevention of antifreeze toxicity.
Signs. The signs of antifreeze toxicity can be divided into three stages. In
stage one the animal may be staggering and appear drunk. In this stage the animal may
vomit, the body temperature may drop, and the animal may slip into a coma. Death can
occur in this first stage. In stage two, the heart and lungs become involved. The
respiratory rate often increases, whereas the heart rate may increase or decrease. In
stage three, kidney failure occurs. The animal may have seizures, eye lesions, and/or
Diagnosis. It can be very difficult to diagnose antifreeze toxicity for several
reasons. First of all, often times no one saw the animal consume the antifreeze.
Secondly, there are few tests on the market available for rapid diagnosis of antifreeze
toxicity. The tests that are available are only accurate within the first 24 hours of
antifreeze consumption. After that time, the test can result in negative results. And
thirdly, because of the variation of signs that can be present, antifreeze toxicity can
look similar to other disorders. Bloodwork can help to rule in the possibility of
Treatment. Treatment should be aimed at decreasing the absorption of the
antifreeze, treating kidney failure, and providing supportive care for the animal.
Intravenous infusion of alcohol has been used with mixed success in the past. The
alcohol will interfere with the binding sites of ethylene glycol thus helping to limit
the amount of antifreeze that can cause damage. A newer medication, 4-MP has become
available for veterinary use within the past several years. It shows more promise and
has fewer side effects than IV administration of alcohol. Even with rapid diagnosis and
quick, aggressive treatment, the overall prognosis for dogs and cats with antifreeze
toxicity is poor. It is estimated that over 78% of animals with antifreeze toxicity die.
Thus if you know or suspect that your animal has consumed antifreeze, you should
immediately seek medical attention.
Prevention. The best way to avoid the accidental poisoning of animals with
antifreeze is to limit their exposure to this substance. Careful disposal of antifreeze
can limit accidental consumption by animals. There are also alternative substances on
the market that do not contain ethylene glycol, the toxic agent of antifreeze.
These products contain propylene glycol, which is a bit safer if animals accidentally
The information provided is for educational purposes only and is not
intended to take the place of your regular veterinarian. Please do not hesitate
to contact your regular veterinarian if you have questions regarding your pet.
Karen Blakeley, DVM, MPH
13 December 2002