Most standard Aspirin tablets are 320mg and baby Aspirin is 80mg. Depending which tablets you have on hand, you may need to give your dog part of a tablet or several. Just make sure that you do not exceed two doses in a 24-hour period – that is, one dose every 12 hours. You should also keep in mind that anything over 30mg per pound is considered toxic, so make your calculations carefully. Proper dosage is important for all dogs, but especially for small dogs because even a minor miscalculation could lead to an overdose.
Aspirin For Veterinary Use in Dogs and Cats - Diamondback Drugs
Dogs on aspirin may have significant changes to their diet and hungerpatterns. It's not uncommon for dogs on this medicine to refuse to eat entirely, or to eat a huge amount at a time and continue to beg for food. With prolonged aspirin use, this can lead to dramatic and often unhealthy changes in weight.
glucosamine and aspirin for dogs - MedHelp
Cats are much more sensitive to aspirin poisoning than dogs. Signs of aspirin poisoning in dogs or cats include gastrointestinal signs (e.g., vomiting, diarrhea, vomiting of blood, black-tarry stool, stomach ulcers, etc.), hyperthermia, respiratory changes, bone marrow suppression, kidney failure, and central nervous system signs (e.g., collapse, extreme weakness, tremors, seizures, cerebral edema). Aggressive treatment is necessary with toxic amounts, and includes decontamination, gastrointestinal protectants, symptomatic and supportive care, IV fluids, and blood work monitoring.
Aspirin and dogs? - Chronicle Forums