The main antidote for antifreeze poisoning in pets has just been pulled by the Food and Drug Administration. Antizol-Vet, also known as Fomepizole, 4-methylpyrazole or 4-MP, is being withdrawn from the market at the request of the drug’s sponsor.
Antifreeze poisoning is one of the most common types of poisoning in dogs and cats, especially in cold climates. Ethylene glycol, the main ingredient in antifreeze, can also be found in hydraulic brake fluid. It has a somewhat pleasant taste that attracts dogs and cats. Just a small amount can be lethal.
Making matters worse, the one antidote useful in initial treatment has been pulled by the FDA.
Paladin Labs (USA) Inc. asked the FDA to withdraw approval because the company has not manufactured or marketed the drug since October 1, 2014. The most recent lot marketed in the U.S. is lot #1319-12A with an expiration date of August 2017.
Dr. Denise Petryk, a critical care specialist for Trupanion Insurance in Tacoma, Washington, said the drug has always been hard to obtain. Many veterinarians have used vodka instead.
“What happens is the poison in the antifreeze forms crystals inside the pet’s organs and the alcohol causes a chemical reaction that will reverse the process,” explained Petryk. Fomepizole will do what a good stiff shot of vodka will do but without the side effects, which is why it has been the preferred treatment.
Prevention is best
Obviously, the best treatment for antifreeze poisoning is prevention. Keep an eye on your garage floor and be quick to mop up any spilled antifreeze.
If you suspect that your pet has ingested antifreeze, get it to your vet immediately because time is of the essence. If you see your dog or cat vomiting or having diarrhea, collect a sample so it can be tested.