On Metacam, Rimadyl, and their NSAID-ish side-effects

Patty Khuly, DVM
Updated: November 02, 2010
Published: March 26, 2009
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For today’s post I’d like to share the contents of a reader’s email for your consideration. This is Catherine Shaffer’s story, one she and I believe is worth sharing with other Dolittler readers. My comments will follow.

Dr. Khuly,

In 2006, we had a ten year old English mastiff named Nala. In October, she seemed to suddenly develop a lot of back pain. She'd been increasingly arthritic, but otherwise in excellent health--ideal weight, etc. The vet ran a metabolic panel, and even commented that all of her enzymes were perfect,whereas normally with a dog that age they see some values drifting out of whack. The vet put her on Metacam (meloxicam) for the pain.

I think Nala had injured herself somehow, we never knew exactly what happened. She began a slow recovery and we dosed her as directed with Metacam hoping she would regain her mobility. Although her injury did seem to heal, and she started moving around more, she also sometimes seemed to be in a lot of pain and was drinking a lot of water and peeing a lot. 

I knew that was a bad sign, but at that point, with her age, we were trying to be minimally invasive with treatments, and so we continued to treat her pain. The drinking and peeing symptoms seemed to abate, and a few weeks later I left for an out of state business trip. Everything seemed normal. 

A day or so later, my husband called to tell me that Nala had vomited up a tremendous amount of blood (it turned out to be half her blood volume) on the living room floor and he took her to emergency. Ordinarily, we would probably have euthanized her immediately, but I was out of state and horribly distraught, so we agreed to let the vet give her two units of blood and treat her. 

By the time I got home, days later, we'd spent $4000 trying to save her. The final diagnosis was liver toxicity from the Metacam, confirmed by necropsy. The drug company (Boeringer-Ingelheim) ended up reimbursing us $1100 for the diagnostics that they added to their post-market reporting, and they also apologized.

I'm a pharma/biotech writer by trade an have a master's degree in biochemistry, with experience working in pharma research. I know that idiosyncratic drug toxicity happens. But when I researched liver toxicity in dogs and cats, I was surprised to find that the rate of toxicity and death seems much higher than would be tolerated in humans (and this isn't even considering the fact that most pet owners would have followed our first impulse, which was to euthanize and not pursue things further--the true rate of toxicity may never be known). 

Also, unlike in humans, the NSAIDs seem to universally cause some stomach irritation, and I have seen recommendations that dogs should be treated proactively for stomach ulcers when they are on NSAIDs, so I suspect that some animals may be more sensitive to COX inhibitors than humans, and that problem is compounded by the fact that they can't tell us they have a stomach ache, not a back ache, when they begin to have symptoms. 

Our vet was really shaken by the whole incident, and she shared with me some uncertainty about using Metacam in her practice. I think ultimately she and most vets come down on the side of feeling that the benefits outweigh the risks, but personally, ever since then I won't give an NSAID to any of my pets. Our kitty had a bladder infection a couple of years ago and we were offered Metacam along with antibiotics. I politely declined, and the kitty did just fine.

I still feel horrible that I did not get Nala into the vet when we noticed the issue with the water and peeing. It was our only real clue that something was dreadfully wrong. I honestly feel that if not for the Metacam, she'd have had another year or two of decent quality of life. Although she was ancient for a mastiff, she was an extremely small and lean one, never more than 105 pounds, and until that accident in October, still enjoyed her daily walk.


Catherine Shaffer


In response to Catherine’s story, and many others I’ve received before hers, I extend my deepest sympathies. Indeed, there’s nothing that seems more senseless than a preventable death. 

An explanation is subsequently in order:

NSAIDs (non-steroidal anti-inflammatory drugs) are the go-to medications for pain in dogs––much less so in cats. Though Metacam is approved for use in cats as a one-time, pain-relieving injection, it is the only NSAID available for them. For dogs, Rimadyl, Deramaxx, Previcox, Metacam and others have been approved by the FDA. 


These drugs do work. They work so well that a several hundred million dollar industry is built around them. Hundreds of thousands of dogs and cats receive millions of doses of these meds every year for pain relief after surgery, following traumatic events, and to manage chronic pain.

But as with any drug, there are side-effects. Liver and gastrointestinal issues are by far the most common unwanted findings, yet these are considered “minor” by the drug manufacturers and the FDA. 

While veterinarians who have seen first-hand the damage NSAIDs can do in no way consider them minor, it’s nonetheless true that our worst horror stories seem minuscule in comparison to the life-saving capacity of these drugs. In fact, the longevity of our large breed canine patients has skyrocketed since they’ve become available. 

Of course, that’s no consolation to those who’ve suffered a devastating NSAID-related death or lengthy medical complication secondary to their use. I hear you all. Which is why your cautionary tales are critical. The more you speak out, the more likely we are to counsel our clients on the down-side of these drugs. We’ll more carefully detail what side effects look like so that we can intervene earlier in severe side-effect cases. 

I’m especially interested in Catherine’s story because she raises some very interesting points about liver toxicity, gastrointestinal side-effects of medications, and the difference in how we manage our human and animal patients. 

In response to her observation: Yes, it’s clear that pet medications, just like pet foods, must leap far fewer hurdles than the human variety. Why else is Celebrex the subject of multi-million dollar class action suits while the owners of Rimadyl side-effect casualties continue to see the drug manufacturers raking it in on these drugs?

It’s because the acceptable risk for pets is far lower than for humans. Which means there’s even more of an onus on responsible veterinarians to explain these well. No excuses.