Benefits and Risks of Rimadyl

By Morgan Benowitz-Fredericks for the Kerry Blue Terrier Foundation
Copyright © 2006 Kerry Blue Terrier Foundation

Background

Rimadyl is an NSAID – “non-steroidal anti-inflammatory drug”. Other NSAIDs include common drugs such as aspirin and ibuprofen. This family of drugs works by inhibiting production of prostaglandins - chemicals produced by the body. Prostaglandins are largely responsible for swelling and the associated pain, but are also important for normal functioning. Rimadyl was originally developed by the company Pfizer for human use, but they found the market too crowded and switched to marketing it for pets. It is primarily prescribed to dogs in two contexts: 1) for dogs suffering from chronic osteoarthritis/difficulty moving (usually older dogs) 2) for short-term pain alleviation (i.e. post-surgery). It comes in chewable tablets, caplets and an injectable form (which is often administered during surgery).

The Benefits

People report wonderful results. For example, a common story is that a dog about to be euthanized because their quality of life was so poor due to arthritis or other chronic pain began taking Rimadyl and got a whole new lease on life – rapidly transforming from crippled to frisky. Many dogs have taken it for years, and many others have taken for a few days or weeks after surgical procedures. There is no question that it is a very effective pain-reliever on both the short and long term.

The Problem

Despite Pfizer’s initial claim that the drug had no known side-effects, it is clear that Rimadyl is moderately-to-lethally toxic to some proportion of dogs (which Pfizer now acknowledges). The consequences range from listlessness to vomiting and bloody diarrhea to destruction of internal organs (liver, kidney and GI tract) and rapid death.
The trick is that if you recognize the symptoms, stop administering the drug and get treatment right away, most dogs can be saved. HOWEVER – very few vets bother to warn patients of the risk, describe “watch out” symptoms, or hand out the information sheet when they prescribe the drug. Additionally, many of the symptoms are things you might associate with a post-surgery dog (wooziness, vomiting, lethargy, disinterest in food), so it can be hard to tell. Certain breeds (labs in particular) appear to be more prone to the toxicity than others, but there aren’t really good statistics out there.

There is currently a class action suit against Pfizer for deaths due to Rimadyl – the plaintiffs claim that the drug was falsely advertised as perfectly safe, with insufficient acknowledgement of the risks. Along similar lines, there is an effort in Pennsylvania to pass legislation REQUIRING vets to hand out client information sheets to accompany any drug they dispense. The lobby’s catch-phrase is: “UN-known risks are UN-acceptable”.

The Confusion

Is Rimadyl more dangerous than other drugs?

It’s not clear to me. What proportion of dogs who take Rimadyl have adverse reactions, and how different is this from other drugs? By most estimates, less than 1% respond badly. It is clear that many millions of dogs have used this drug without problems, but there are also thousands of reports of serious adverse effects (according to USA Today, the FDA has 13,000 reports, while Pfizer has received 20,000). There are at least 2 factors which make these numbers difficult to interpret. 1) Despite the fact that Pfizer acknowledges that Rimadyl’s role in many cases is “probable,” it can be difficult to determine if the sickness or death was caused by the drug, especially because it is often prescribed to old and ill dogs, who were already sick and potentially close to death. 2) On the other hand, it is highly unlikely that reports were filed with the FDA or Pfizer for all victims. In general, this entire category of drugs (NSAIDs, including aspirin and ibuprofen) can induce similar reactions, and similar care should be taken with them.\

What the Kerry Blue Terrier List Members Said

We polled Kerry Blue Terrier owners about their experiences with Rimadyl through the Foundation website and list-serve. 36 people responded to the poll. 83% (30 dogs) had used the drug either short or long term and not experienced any problems. 17% (6 dogs) used it short-term and had a suspected or confirmed adverse reaction. No one reported a suspected or confirmed adverse reaction after long-term use.

We also asked for comments from the group. At least 4 people described the adverse reactions their Kerries had to Rimadyl (symptoms ranging from lethargy to bloody stool and vomiting, to elevated liver enzymes indicative of poor liver function). They all caught the symptoms and took the dogs off the drug. No deaths were reported, although several people knew of dogs who died after taking Rimadyl. Some people reported what their vets said: one specifically said he’d never prescribe long-term Rimadyl use for any terriers (not clear why he singled out terriers), another only dispenses it if the client specifically requests it. Several other Kerry owners felt that homeopathic medicine was far more effective and safer. For older dogs and joint pain, glucosamine, chondriotin, Ester C, yucca and other natural supplements were suggested, although I would remind you that naturally-derived substances are not always side-effect free, either, and should be researched as well.

My Conclusion

This is an effective drug which has been used by millions of dogs to alleviate pain and improve quality of life. There are serious risks associated with its use, but they may be reasonable risks to take. HOWEVER – due to chronic failures on the parts of veterinarians to provide the necessary information (either in the form of a verbal explanation or an information sheet from the drug company), (a) most people do not get to make a decision after weighing the benefits against the risks because they are not aware that the risks exist.
(b) most people cannot identify a dangerous adverse reaction when it occurs because they are not aware of the symptoms to watch for.

I would strongly encourage pet owners to research Rimadyl and any drug they consider giving to their animals. Some of the important pieces of information to determine are:

What medical conditions would put an animal at higher risk for an adverse reaction (e.g. liver or kidney problems in the case of Rimadyl)
What drugs should NOT be taken simultaneously (“contra-indications”)?
What are the symptoms of an adverse reaction?
Are there tests available to monitor my animal to make sure the drug is not causing damage? (For Rimadyl, regular blood panels to check liver function are recommended for long-term users.)

You may get this information from your vet, but also take the time to obtain and carefully read the package insert that drug companies provide with the drug (vets often do not pass this along: ASK for it). If you are concerned that Rimadyl might not be suitable for your pet, talk to your vet before any surgical procedure: a Rimadyl injection is often part of standard procedure for operations (i.e. spaying or neutering), and some vets do not consult owners first.

Symptoms of an adverse reaction to Rimadyl

There is a consumer awareness campaign called “B.A.R.K.S.” – “Be Aware of Rimadyl’s Known Side-effects”. They list the following symptoms of an adverse effect:

vomiting
loss of appetite
change in drinking habits
excessive urination
diarrhea
regression in house training
blood in the stool
uncharacteristic aggression
lethargy
wandering in circles
stumbling
loss of balance
jaundice

If notice any of these symptoms in a dog taking Rimadyl, stop giving the drug immediately and take you dog to the vet ASAP.

For More Info

This page from the “Senior Dog Project” (thanks to Youlia Anderson for directing me here) has great information. The FAQs are a good place to start, but I would also point to the comments from veterinarians – many of whom are frustrated because they feel this drug is getting an unfairly bad reputation: http://www.srdogs.com/Pages/rimadylfr.html

Another site with assorted Rimadyl info and links: http://www.doglogic.com/rimadyl.htm The link directly to Pfizer’s Rimadyl site:
http://www.rimadyl.com Here is a shortcut to the detailed information and warnings from Pfizer, including descriptions of the adverse effects:
http://www.rimadyl.com/display.asp

A site about many types of adverse reactions that dogs may have (other drugs, vaccines, etc):
http://dogsadversereactions.com/

The mailing list http://groups.yahoo.com/group/doghealth2/ is comprised of hundreds of dog owners whose dogs have had adverse reactions (or died) from adverse side effects of Rimadyl and similar drugs.

From the Wall Street Journal - March 2000 - http://www.judyshealthcafe.com/articles/rimadyl-warning.html

Finally, here is an excellent site with information about WHERE TO FIND MORE information about any drugs you may consider giving your pets:
http://www.veterinarydruginfo.com

Disclaimer:

I am NOT a veterinary or medical professional. I have tried to provide access to useful information to help inform decisions about administering Rimadyl to your dog.