CVM: Pentobarbital in dog food not a threat

Rockville, Md.-

The amount of sodium pentobarbital in dog food is so minute, it's highly improbable it would pose any animal health risk, reports the Food and Drug Administration (FDA).

In a government-funded risk assessment report released Feb. 28, scientistsconcluded that the low levels of exposure to pentobarbital that dogs mayabsorb in food should not raise veterinary concerns.

"The major purpose was to determine if indeed there was enough pentobarbitalin dog food to harm the animals," says Stephen Sundlof, DVM, directorof FDA's Center for Veterinary Medicine. "The investigation is nowclosed. Nothing in the sample indicated any reason for alarm."

In the 90s, reports from veterinarians were sent to CVM indicating thatpentobarbital, an anesthetizing agent used for dogs and other animals, wasno longer as effective in dogs.

"Veterinarians had raised the issue about whether there was substantialpentobarbitol in the pet food," says Sundlof. "They were reallydriving this investigation."

CVM officials then studied whether exposure to pentobarbital in dog foodcould reduce the impact of pentobarbital as a drug.

Coinciding with the investigation, scientists analyzed whether randomsamples of pet food contained rendered remains of dogs and cats, becausepentobarbital is also used to euthanize animals.

Results

First, scientists found pentobarbital survived the rendering process."My guess originally was that because rendering is a destructive process,I'd be surprised that any pentobarbital would survive the process,"says Sundlof.

Then it was determined that pentobarbital was likely to be present inthe rendered feed.

CVM measured traces of pentobarbital down to 2 parts per billion of theagent in dry dog food.

The results demonstrated an absence of any material that would have beenderived from euthanized dogs or cats. The sensitivity of this method is0.005 percent on a weight/weight basis. Now the assumption is pentobarbitalresidues are entering pet foods from euthanized, rendered cattle or horses.

Two key findings:

1. Dogs that received 150 and 500 micrograms pentobarbital oncedaily for eight weeks had statistically higher liver weights (relative tobodyweight) than animals in the control groups.

2. The activity of at least three liver enzymes was statisticallygreater than controls at doses of approximately 200 micrograms pentobarbitalper day or greater.

Researchers found no statistical differences in relative liver weightor liver enzyme activity between the group receiving 50 micrograms pentobarbitalper day and the controls. Based on the data, CVM scientists determined thatthe no-observable-effect level for pentobarbital was 50 micrograms of pentobarbitala day.