Antifreeze antidote withdrawn

The only commercial antidote for ethylene glycol poisoning is off the market, but poison control experts noted that veterinarians have alternatives.

Paladin Labs had stopped making Antizol-Vet (fomepizole) by Oct. 1, 2014, and the Food and Drug Administration approved in April the company’s request to withdraw the drug’s approval.

Dr. Ahna Brutlag, associate director of veterinary services for the Pet Poison Helpline, said that prior to the withdrawal, Antizol-Vet had been largely unavailable and little used when it was available. The product was expensive, and veterinary clinics have been responding to suspected poisonings with human-use fomepizole, compounded versions, or ethanol.

Dr. Tina Wismer, medical director for the American Society for the Prevention of Cruelty to Animals’ Animal Poison Control Center, said several pharmacies have been producing compounded versions of the product, and, like Dr. Brutlag, she noted that veterinarians also have been using the more old-fashioned and inexpensive treatment of administering ethanol-containing alternatives such as the rectified spirit Everclear or vodka. She expects veterinarians will be able to treat animals with little trouble.

Both poison control officials said ethylene glycol poisoning numbers have remained level in recent years. For example, Dr. Wismer said the ASPCA hotline received 305 calls about such poisonings in 2014, 328 in 2013, and 325 in 2012.

Jad Isber, director of international and base business for Paladin Labs, said the company requested the withdrawal because low demand made continued production unfeasible. Antizol-Vet was sold only in the U.S., and Paladin does not plan to make it for other markets.