RimadylŠ Are the Risks Worth It?
Bud Siemering, DVM     

Rimadyl (carprofen) was introduced in the spring of 1997. Pfizer marketed
this drug very aggressively to the public and to veterinarians. Soon we had
clients coming into our exam rooms asking about the new "wonder" drug they
were hearing about on television. Many veterinarians immediately turned to
this drug as the drug of choice for joint pain and even postoperative pain.
Since the spring of 1997 things have changed.    

The first thing that has changed is Pfizer's product information sheet
distributed with all bottles of Rimadyl. The second thing that has changed
is that we now know Rimadyl can cause devastating liver damage and even
death. In the first product information sheet (January 1997) the paragraph
on adverse reactions states: "During investigational studies, no clinically
significant adverse reactions were reported." If you read the adverse
reaction section in the new product information sheet there are 10 paragraphs
of varying types of reactions along with a special toll free number to call
to report adverse reactions. In the first production information sheet there
was no mention of Rimadyl causing death. The new product information sheet
states: "The side effects of this drug class, in rare situations, may be
serious and if corrective action is not taken may result in hospitalization
and even fatal outcomes." The precautions section also states that all old
dogs should have a geriatric exam and baseline hematological and serum
biochemical studies prior to administering this drug.    

At SouthPaws we have seen several dogs who presented in liver failure and who
were "healthy" prior to taking Rimadyl. Two have died.    

Rimadyl is not my drug of choice for joint paint due to osteoarthritis.
Piroxicam is my drug of choice. Next in line would be etodolac. I have been
using both of these drugs in the human form for the past eight years.
Piroxicam has the advantage of being administered only every other day after
a loading dose is given. Etodolac has now been approved for use in dogs and
is distributed for Fort Dodge as EtoGesic. This drug, according to the
scientific literature, appears to be the least likely to cause
gastrointestinal and renal toxicity because it inhibits COX-1
(cyclooxygenase) to a lesser extent than any other NSAID. I do see an
occasional dog who develops gastrointestinal disturbance when taking either
of these drugs, however, this is rare. Cats can take piroxicam (0.3mg/kg
every other day).    

There is nothing wrong with using Rimadyl if you select your patients
carefully and monitor their blood values while they are taking it. Many old
arthritic dogs who are referred to me, I find, are taking Rimadyl and have
not had blood tests run prior to taking the drug or during the time they have
been taking it. I believe these dogs are at risk patients and would
recommend blood counts and chemistries prior to administering the drug and
repeating the tests are least every 4 months. As with all NSAIDS, concurrent
use of corticosteroids is inadvisable. This could cause serious
gastrointestinal side effects including perforated gastric ulcer.

In summary, not every dog responds the same way to a given NSAID. This is
why there are so many forms of these drugs on the human market. If a
particular drug does not work well for your patient, try one of the others.
If you choose to use Rimadyl, please follow the manufacturer's
recommendations and maybe go one step further with follow-up blood testing.
The best alternative would be to investigate and offer an alternate NSAID
like Feldene or Etogesic.

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