You can find snaking threads on animal health forums across the Web on the dangers of Rimadyl—with horror stories to support the menace it represents to dogdom. Rebuttals are relatively few as most of the cautionary tales are compellingly dreadful:

My dog had been on Rimadyl for two weeks when his stomach ruptured and he died of internal bleeding.

Mine had never had any liver problems until he went on Rimadyl. Now he has liver cancer.

My dog couldn’t take Rimadyl. It gave him bloody diarrhea. Why do vets persist in dispensing this deadly drug?

Rimadyl (Carprofen) is an NSAID (non-steroidal anti-inflammatory drug) like aspirin or Advil. They are used to treat pain in the short term, but are approved for long-term use, as well. Because human NSAIDs cause gastrointestinal problems in a large percentage of dogs, vets have typically never used them beyond a one to three day period. Now that we have Rimadyl, Derramax, Previcox, Metacam, and Zubrin (all NSAIDs approved for use in dogs) we almost never recommend the human versions.

All NSAIDs (not just the Rimadyl) can cause the same sinister side effects in dogs as in humans: gastrointestinal bleeding and liver disease (not liver cancer). Both are potentially deadly to dogs. While severe liver effects are far more uncommon, it seems to be the most feared consequence among my clients and among posts I`ve read online. I see far more GI issues, though, and these can often be managed with lowered doses, a change in the kind of NSAID used, and/or the addition of other drugs such as the opiate, tramadol.

For my part I never dispense this medication without stern warnings to call me should they notice any GI symptoms such as vomiting, diarrhea, weight loss or lack of appetite. Dogs with GI sensitivity to NSAIDs almost always show these symptoms long before bleeding occurs. In many cases we stop the drug altogether and look for non-NSAID alternatives (precious few for chronic pain).

I also explain the potential for damage to the liver. In our practice, bloodwork to examine the health of the liver is mandatory before chronic use is considered. Moreover, follow-up bloodwork is periodically required for refills. Short-term users (for a few days after a spay or dentistry, for example) have not been shown to suffer liver effects.

In one case our practice had, Rimadyl`s manufacturer (Pfizer) paid for a dog’s liver biopsy after a client was convinced her Doberman acquired liver disease after using it for a few weeks. Although the biopsy showed a disease common to Dobermans (chronic active hepatitis) and uncommon for NDSAID toxicity, Pfizer paid for the dog’s care. Since then we’ve never had another case like this.

Despite what I consider my prudent approach to dispensing this drug (and others like it), I have many clients that call back, weeks after their dog has taken a miraculous turn (according to their owners), with anguished questions on the safety of the medication. Many want to stop the drug. And so some do. But most call back months later for refills. Their dogs` lameness and weight loss due to muscle atrophy is too great for them to do otherwise.

Whenever I receive a call like yesterday’s I give my pros and cons speal. These are your options. This is why I would recommend this drug. Sure, we can try X, Y, and Z for a time to see if it will be sufficiently effective but if it doesn’t work I hope you’ll reconsider.

After all, studies have convincingly demonstrated that, without anti-inflammatory medication, dogs with pre-existing arthritis and muscle atrophy will decline much faster, while experiencing effects consistent with severe pain (such as lameness and the inability to rise with ease). What would you rather have? Certain chronic pain or the possibility of [usually reversible] GI bleeding and an even smaller risk of liver toxicity? Your call.

Owners are always encouraged to use glucosamine and chondroitin sulfate (a nutritional supplement) along with the NSAIDs and to use as little of the drug as possible to achieve the desired effect. One notable study this year demonstrated that some dogs can achieve similar levels of pain control on the glucosamine and chondroitin sulfate alone. And that’s ideal. Vets don’t like to use drugs. We do so only when the drug’s benefits outnumber its potential risks.

Above all do no harm is our guiding principle, but without the use of drugs (where there’s always a potential to do harm) where would medicine be today?