Side Effects of Aspirin in Dogs

Veterinarians prescribe aspirin, scientifically known as Acetylsalicylic acid, for dogs for many of the same reasons much the way human doctors tell us to use it. Keep a close eye on your dog for signs of side effects since he can't tell you if he's feeling funny.

  1. Upset Stomach

    • One the most common symptoms seen in dogs taking aspirin is an upset stomach. This usually can be reduced by giving aspirin with food or using buffered aspirin.

    Ulcers

    • Aspirin may cause gastric or intestinal ulcers. Signs to watch for are: stomach upset, loss of appetite, bloody vomit and black, tarry stools (melena). In rare cases, perforations may even take place causing life threatening, peritonitis.

    Kidney Failure

    • Because aspirin tends to reduce the blood supply to the kidneys, this may cause kidney failure in dogs. Symptoms suggesting kidney failure are: vomiting, diarrhea, loss of appetite, lethargy, increased drinking and increased urination and dilute (watery) urine.

    Blood Clotting Problems

    • Aspirin thins the blood and may cause blood clotting problems, especially in dogs that are undergoing surgery, have bleeding disorders or are injured. Signs of blood clotting problems in dogs consist of unexplained bleeding, pin point bruises under the skin (petechiae) and pale gums, suggesting anemia.

    Allergies

    • While rare, allergy is a possibility. Owners suspecting an allergic reaction should take their dog to closest veterinary emergency center as soon as possible.

    Warning

    • Be careful not to overdose the dog. This can cause aspirin toxicosis, which can be fatal. A baby aspirin may be toxic to a dog weighing two pounds or less. Never guess. Give only the amount your vet recommends for your pet.