An industry-wide shortage of the main drug used for euthanasia is forcing veterinarians to conserve supplies and consider using alternate methods to humanely end animals’ lives.

Pentobarbital, the active ingredient in the most commonly used euthanasia drugs for horses and small animals, has been in short supply since the beginning of the year. It was added to the U.S. Food and Drug Administration’s list of animal drug shortages this month. The shortage was not reported widely at first; veterinarians around the country began to notice the issue as they tried to replace dwindling supplies, only to learn the drugs were backordered and largely unavailable.

“None of us knew. I went to order a bottle; it was out of stock,” said Jill McNicol, DVM, of Cool Springs Equine LLC in Leetonia, Ohio. She soon learned from her drug distributor representative that they, too, were scrambling to fill orders.

In response, organizations including the American Veterinary Medical Association, American Association of Equine Practitioners and the Companion Animal Euthanasia Training Academy are urging veterinarians to conserve supplies by adhering strictly to dosage guidelines and have shared guidance on alternative euthanasia methods.

The AAEP is aware of the shortage and has published guidelines for preferred humane euthanasia methods that offer practitioners a number of alternatives, including gunshot, captive bolt or several other combinations of drugs, spokesperson Sally Baker said.

“The AAEP joins the AVMA and other veterinary organizations in closely watching how the pentobarbital shortage may affect veterinary care,” Baker said in an email. “We are not at this time receiving phone calls from our members about this issue, and so right now practitioners appear to be managing the situation. The AAEP’s euthanasia guidelines provide information to veterinarians about options other than pentobarbital for the humane euthanasia of horses.”

Horse owners should recognize that those alternative methods, while they may involve a different process from pentobarbital euthanasia, are humane in a veterinarian’s trained hands.

“I would encourage horse owners to bear with their veterinarian and be open to alternative methods that this shortage will inevitably necessitate,” said Bonnie Kibbie, VMD, cVMA, cIVCA, of Balanced Care Equine in Unionville, Pennsylvania. “The AAEP’s guidelines for humane euthanasia and accepted methods are well-researched and designed to minimize animal suffering. Things like gunshot or captive bolt sound scary, especially compared to a simple injection, but when done correctly are instantaneous and do not cause suffering or pain.”

While veterinarians hope the shortage will be resolved this summer, the FDA’s Center for Veterinary Medicine said it is too soon to speculate on exactly when pentobarbital and pentobarbital combination drugs will be readily available again.

“FDA’s Center for Veterinary Medicine is aware of the issue and has reached out to sponsors/manufacturers of pentobarbital products to determine the extent of the shortage and possible avenues for resolution,” spokesperson Anne Norris said in an email. “Although we continue to evaluate the situation, it appears that various market factors are impacting the supply of finished product. All parties are working cooperatively with the FDA and the U.S. Drug Enforcement Agency to address the availability of pentobarbital active pharmaceutical ingredient. This is an ongoing process, and until the agency learns more, it would be premature to speculate about when the shortage will be resolved.”

Euthanasia solution is still being manufactured, she noted.

Until the supply chain is back to normal, however, veterinarians are taking extra steps to preserve their supplies.

“To conserve euthanasia solution, a wise choice is to dial back how much is used,” CAETA founder Kathleen Cooney advised in a recent blog post addressing the shortage. “When euthanasia is warranted to end patient suffering, only using the recommended dose is called for. Many practitioners give a little extra to ensure death is complete, but it’s really not needed.”

McNicol, who treats both small animals and horses, says she and her fellow veterinarians have been able to stretch supplies thus far by adhering strictly to AVMA guidelines, and they are getting new orders, albeit infrequently. Veterinarians are doing their best to ensure that the euthanasia process remains as smooth as possible for animals and their owners alike, she said.

“From a veterinarian’s perspective, we deal with [medication shortages] often; it’s just usually not so impactful,” McNicol said. “The reason pentobarbital has been used so long is it’s worked so well.”

Most of the alternative drug combinations that can be used in place of pentobarbital solution involve anesthetizing the animal first, which, particularly for small animals, changes the look, the time and potentially the cost of the process, all of which could be upsetting for the pet owner.

“Be kind to your vet,” she said. “I’ve put down a lot of animals—a lot of horses, a lot of small animals over the years—and it’s still tough. When it’s harder on us, it’s harder on the client; when it’s harder on the client, it’s harder on us.”