Dear Doctor – Different vets with different views on aspirin?
Q. In your October article on “Sharing the Medicine Chest” with your dog, you made no mention of aspirin. My veterinarian has prescribed 81 milligrams of aspirin twice a day for my 13-year-old border terrier, who has trouble climbing stairs and going for her walks. My friend’s vet has told her not to give aspirin to her German shorthaired pointer. What is the verdict on whether to use aspirin for pain in dogs?
Webster, New York
Dear Ms. Dunn,
A. Veterinarians do prescribe aspirin for dogs on occasion. The operative word is “prescribe,” says Alicia Karas, DVM, who runs the Pain Clinic on Tufts’s veterinary campus, because while it is available over the counter for people, professional counseling about its risks for dogs and about the amount of aspirin to give, if any, can come only from your vet. That’s why it may be indicated for some dogs but not others.
Why might a vet prescribe aspirin? Aspirin and drugs in the aspirin family, all called non-steroidal anti-inflammatory drugs, or NSAIDs, are quite often beneficial for arthritis pain control. That said, they can have some serious side effects, such as GI ulceration, vomiting, and sometimes out-and-out perforation of the GI tract, which is often fatal.
How often do these untoward outcomes occur? We don’t know. Aspirin is not an FDA-approved drug for dogs; its use by vets is what is called off-label. Therefore, manufacturers of aspirin do not keep track of reported adverse effects in our canine pets. For those NSAIDs that are approved for use in dogs — Rimadyl, Deramaxx, Previcox, and Metacam, for instance — manufacturers are required to tell the FDA about each adverse effect that is reported to them.
The use of aspirin is further complicated by the fact that it is unique among NSAIDs because it inactivates platelets, which are important for blood clotting. Ulceration of the lining of the stomach caused by aspirin could potentially be exacerbated by poor clotting, so aspirin may pose an additional risk compared to NSAIDs approved for dogs. Again, that risk is unknown because of the lack of a reporting mechanism for this drug.
The bottom line, says Dr. Karas: Give aspirin to your dog only if your vet thinks it is safe. Your dog’s doctor obviously feels that, given her health history, 81 milligrams twice a day (two baby aspirins per 24-hour period) is okay. Your friend’s dog may very well have a health profile that makes an NSAID like aspirin risky to prescribe.
If at any point your own dog develops vomiting, diarrhea, dark tarry stools, lethargy, or a refusal to eat, stop giving the aspirin immediately and speak to her veterinarian. These are all potential signs of ulcers, which can progress to very serious consequences without appropriate medical intervention.
Finally, if your dog is feeling well on aspirin and can get around better because of it, don’t increase the amount prescribed in the mistaken belief that if a little is good, more is better. It’s not.
This article originally appeared in the February 2017 issue of Tufts Your Dog