Recently it has been clearly documented that grapes
and raisins can cause kidney failure in dogs. It is unclear whether this is a
new problem, or if the toxic nature of grapes and raisins became recognized
after the establishment of a computerized animal toxicity database about 25
years ago. Whatever the case, the number of identified cases of illness or
death in dogs after they have eaten raisins or grapes is on the increase.
types of grapes and raisins are toxic to dogs?
The type of raisins or grapes does not appear to
matter, with reported cases of toxicity occurring after dogs have eaten
seedless or seeded varieties, commercial or homegrown fruits, and grape
pressings from wineries.
is the toxic dose?
Since raisins are dried and therefore more concentrated
than grapes, it appears that raisins are relatively more toxic than grapes.
According to the Merck Veterinary Manual, the estimated toxic dose of grapes is
32 grams of grapes per kilogram of body weight (0.5 ounces per pound) and for
raisins it is 11-30 g/kg (0.18 to 0.48 oz/lb).
are raisins and grapes toxic?
Currently, it is not known why grapes and/or raisins
are toxic. Some researchers suspect that a mycotoxin (a toxic substance
produced by a fungus or mold) may be the cause. However, so far no toxic agent
has been identified. Since it is currently unknown why these fruits are toxic,
any exposure should be a cause for concern.
should I do if my dog eats grapes or raisins?
If you suspect that your pet has eaten any grapes or
raisins, please contact your veterinarian immediately. Do not waste any time.
Since there are still many unknowns associated with this toxicity, it is better
not to take any chances when it comes to your pet's health. At the Fredonia
Animal Hospital, we have seen symptoms appear witin 30 minutes of ingestion.
are the symptoms of grape or raisin toxicity?
The most common early symptom of grape or raisin
toxicity is vomiting, usually within a couple of hours after ingestion. Next,
the dog may develop diarrhea, excessive thirst, excessive urination or
Acute kidney failure from a toxic dose of grapes or
raisins will usually develop within 1-3 days. Symptoms of kidney failure
include vomiting, diarrhea, dehydration, abdominal pain, and tremors or
seizures. If the toxicity progresses, the kidneys will shut down and the dog
will not produce any urine. The dog may develop foul breath (its breath will
have the odor of urine) and in some cases ulcers may form on the gums at the
locations where the salivary ducts drain. As the kidney failure progresses, the
dog's blood pressure will elevate dramatically and the dog will usually lapse
into a coma.
is the toxicity diagnosed?
Unfortunately, the symptoms of grape or raisin
toxicity are non-specific, and are similar to kidney failure from many other
causes. Instead, your veterinarian will base a presumptive diagnosis of this
toxicity based on a history of eating grapes or raisins, or the presence of
pieces of grapes or raisins in the dog's vomit.
Your veterinarian will recommend diagnostic tests
such as a Complete Blood Count (CBC), a Serum Biochemistry Profile and a
urinalysis to assess the amount of damage to the kidneys, which will help
determine what the dog's prognosis is for recovery.
there an antidote?
is this poisoning treated?
The goal of treatment is to block absorption of the
toxins and prevent or minimize damage to the kidneys.
If treatment is started within 2 hours after the
grapes or raisins were eaten, your veterinarian will induce vomiting to
eliminate the fruits from the stomach, and will administer activated charcoal
to block further absorption of the toxins. The patient will be put onto
intravenous fluids to help flush any absorbed toxins out of the body as quickly
as possible and to help maintain kidney function. Drugs to control nausea or
vomiting and to help maintain blood flow to the kidneys will be administered as
During the course of treatment, your veterinarian
will monitor the patient's kidney values to assess the response to treatment
and determine whether the treatment needs to become more aggressive.
is the prognosis for recovery from poisoning from grapes or raisins?
Prognosis depends on many factors, including how
many grapes or raisins were eaten, how ill the dog was when treatment was begun
and whether the clinical signs improve once treatment is started.
If the dog only ate a few grapes or raisins, and
received immediate treatment, the prognosis is reasonably good. If the kidneys
shut down so that no urine is produced, the prognosis is poor. It is important
to realize that the kidneys have very little capacity to regenerate or repair
themselves, and once the kidneys are damaged, they will not function as well as
they did before the episode. Your veterinarian will estimate the prognosis for
your dog based on its clinical signs and individual situation.
can I prevent this problem?
Keep all grapes and raisins, or foods containing
grapes or raisins, out of reach of your dog. Do not share any food that may
contain grapes or raisins with your dog, and especially do not use grapes as
treats for your dog.
other common foods are toxic to dogs?
Onions, chocolate, cocoa, macadamia nuts, avocados
and foods containing the sweetener xylitol can also be fatal.
other animals at risk?
So far, grape and raisin toxicity has only been
identified as a problem in dogs. Since there are still many unknowns associated
with this toxicity, it would be prudent to avoid giving ANY grapes and raisins
to your pet dog or any other pet.