Ingestion of grapes or raisins can be toxic to dogs. Ingestion of grapes and raisins does not appear to cause toxicity in all dogs but can cause acute kidney failure in some dogs. It has not been documented in cats.
According to the ASPCA Animal Poison Control Center, between January 2001 and August 2004, over 200 calls were made to the ASPCA Animal Poison Control Center involving potential exposures to grapes or raisins in dogs.
The documented toxic grape or raisin dose range is 0.32 to 0.65 oz/kg (0.15 to 0.32 oz/lb). This means a 20 pound dog can eat as little as 3.2 ounces and have signs of toxicity. Studies suggest the lowest documented toxic raisin dose is 0.1 oz/kg and 10 to 12 grapes in a 20 pound dog. Raisins are 4.5 times more concentrated than grapes on an oz per oz basis.
So far, at least 10 dogs have been officially reported to the ASPCA Animal Poison Control Center. The amount of grapes or raisins ingested has been between a few ounces and 2 pounds, and dogs ingesting these large amounts have developed kidney failure. Aggressive and sometimes prolonged treatment may be necessary to give the affected dog a chance at survival; without treatment death is possible.
Despite testing, the reason for the kidney failure and the amount necessary for toxicity remains unknown. For now, any dog that ingests large amounts of grapes or raisins should be treated aggressively, so contact your veterinarian immediately if ingestion has occurred. All cases of grape or raisin ingestion should be considered potentially serious. The ASPCA Animal Poison Control Center is also asking that veterinarians and owners call them to report the ingestion, treatment and results. What to Watch For
These signs generally can start within a few hours and progress over 24 to 48 hours. Vomiting – often within 2 hours of ingestion
As the disease progresses into kidney failure, you may see the following:
Lack of appetite
Diagnosis is often based on history of exposure and ingestion, evidence of grapes or raisins in the vomit or stools and onset of clinical signs of kidney failure.
Diagnostic tests recommended may include a complete blood count, diagnostic profile, urinalysis and abdominal radiographs.
Even those dogs whose kidneys do not appear to be affected should be treated aggressively. Preventing kidney damage is key to survival. Grape and Raisin Toxicosis is treated as "Acute Kidney Failure". There is no unique treatment for this condition. For more information go to Acute Kidney Failure.
If ingestion occurred recently (within 6 to 8 hours), your veterinarian will likely induce vomiting to try to remove a significant amount of grapes or raisins.
Activated charcoal can be used to help prevent absorption.
Initial blood tests to determine the status of kidney function. After 48 hours, repeat blood tests are done to determine if the kidney function has remained normal. Even when the kidney values are normal, repeat blood tests should be done 5 to 7 days later to make sure the kidney values remain within normal limits, especially since the cause and disease process involved in grape ingestion is unknown.
Hospitalization and treatment with intravenous fluids. Two days of intravenous fluid therapy is often recommended to help prevent damage to the kidneys. If kidney damage has occurred, intravenous fluid therapy is continued until the blood tests indicate the kidneys are functioning.
Additional drugs may be used to treat inadequate urine production. Drugs may include mannitol, furosemide and/or dopamine
The prognosis of grape and raisin toxicosis is variable depending on the severity of clinical signs in the pet. If caught early and decontamination procedures such as vomiting and activated charcoal are instituted before clinical signs, the prognosis is good. Once acute kidney failure occurs, the prognosis is guarded. Some reports indicate that only approximately 50% of dogs survive the disease.