If your dog ingests grapes or raisins, it is best to contact the ASPCA Animal Poison Control Center (888-426-4435), where they have specially trained staff who provide assistance to pet owners and specific diagnostic and treatment recommendations to veterinarians. Because affected dogs could die, dog owners should stop feeding their dogs grapes, raisins and any food containing grape extracts.
If ingestion should occur, it is recommended that you seek veterinary assistance immediately to initiate aggressive medical management. For more information on the toxicity of grapes or raisins, visit www.apcc.aspca.org.
Recently, veterinarians have recognized this new poisoning in dogs: severe acute kidney failure following ingestion of grapes or raisins.
What causes it?
The specific poisons involved in this toxicosis have eluded identification. Fungal, pesticide and heavy-metal causes have been ruled out. It appears from recent unpublished data that the toxic component is within the flesh of the grape/raisin, not the seed.
What species are affected?
There are reported cases in dogs, and sporadic reports that cats may be affected. Most cats will not readily eat grapes or raisins, and this may be the reason for the lack of data in this species. Birds do not seem to be affected.
How much is dangerous?
The lowest recorded amounts that caused kidney failure in dogs are: for grapes, 0.3 ounces of grapes per pound of body weight; and for raisins, 0.05 ounces per pound. In other words, this would mean a 50-pound dog could be poisoned by eating as little as 15 ounces of grapes, or 2 to 3 ounces of raisins.
However, smaller amounts could also cause problems - we really don't know exactly what the minimum dose is.
Not every dog or cat is susceptible. Many animals can tolerate large quantities of grapes or raisins without problems, and at this time no one knows what the main risk factors are that make one animal susceptible to being poisoned.
What about grape seed extract or grape juice? This appears to be safe.
Toxicity has been associated with seedless grapes, so the toxin is unlikely to be within the seeds. It is then possible that grape seed extract is safe to use - however, this has not been conclusively proven. The reason this is important to know is that grape seed extract is a powerful antioxidant that may be helpful in the treatment of arthritis and other inflammatory conditions, and some dog owners use this in their older dogs.
If your dog eats grapes or raisins, the smartest thing to do is to make the dog vomit immediately. A tablespoon of hydrogen peroxide given by mouth will usually accomplish this within five or 10 minutes.
However, if there is any chance that some grapes or raisins have not been vomited up, the safest thing to do is take your dog to your veterinarian. The appropriate treatment to minimize the risk of kidney damage is to administer large amount of IV fluids for 36 to 72 hours.
What is the prognosis?
The prognosis in cases where kidney failure develops is guarded, at best. This is medical jargon that means, very roughly, the chances of survival are 50/50. Prognosis is good if caught immediately after a dog has eaten the grapes or raisins.
--Dr. Franklin Utchen, shown with his dog Tory, has been practicing veterinary medicine in the San Ramon Valley since 1989 and currently co-owns Bishop Ranch Veterinary Center & Urgent Care. For questions or comments e-mail firstname.lastname@example.org.
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