Yogi's really making up for lost romping time!
After being on an IV for almost a week having his liver flushed even with Milk Thistle his liver enzymes are moving back down to the normal count where they were before taking Rimadyl for only a week. Yogi's AST (SGOT) level was 486 and the reference range is between 15-66. His ALT (SGPT) count was 2859 the reference range is 12-118.
It was not at first clear that Labradors were particularly susceptible to Rimadyl toxicity, since Labradors, more than other breeds, have joint problems and are given Rimadyl for relief. However, Pfizer's report on side effects that occurred during the drug's initial post-approval phase states, ". . . approximately one fourth of all hepatic reports were in Labrador Retrievers." This appears to be an alarmingly high incidence and should guide your choice of using Rimadyl if your dog is a Lab.
Rimadyl should never be given along with any other non-steroidal anti-inflammatory drug (NSAID) such as aspirin, or along with any corticosteroids such as prednisone, prednisolone, or dexamethasone. The University of California at Davis recommends a two week "rest" period when changing from any NSAID to carprofen or from carprofen to another NSAID.
Carefully decide whether Rimadyl is appropriate for your dog by weighing the benefits against the risks. Keep in mind that it has been widely reported that many veterinarians are not fully informed about this drug. As Stephen Fried so eloquently summarizes in his book, Bitter Pills: "It's a question of whether the potential benefit is worth the risk and whether the patient understands that risk -- which depends on whether the doctor knows enough about the drug to really explain the risk."
If you decide your dog may benefit from Rimadyl and it is worth the risks involved, tell your vet that you want to determine the lowest possible dosage that can be used to obtain relief. Although the recommended dosage is 1mg/pound of weight twice per day, your dog may get relief at a lower dosage. A lower dosage could be instrumental in avoiding toxicity (although this is not guaranteed). In addition, your vet may recommend that Rimadyl be used for short periods (several weeks), or intermittently, as needed, with time off (several weeks) to give the dog's liver time to recover.
Insist on baseline tests and continued monitoring of the relevant functions during the entire time your dog takes the drug. Pfizer only recommends this and does not indicate that it is a requirement.
To avoid the gastric upset that occurs in some dogs, the drug should be given with food. Pepcid may also be used concurrently to control gastric upset.
As soon as your dog begins Rimadyl therapy and during the entire time he takes it, watch for the following symptoms, all signs of potential life-threatening reactions to the drug:
loss of appetite
change in drinking habits (refusal to drink or increased water consumption)
unusual pattern of urination, blood in the urine, sweet-smelling urine, an overabundance of urine, urine accidents in the house
black, tarry stools or flecks of blood in the vomit
lethargy, drowsiness, hyperactivity, restlessness, aggressiveness
staggering, stumbling, weakness or partial paralysis, full paralysis, seizures, dizziness, loss of balance
jaundice (yellowing of the skin, mucus membranes and whites of the eyes)
In the presence of any of these symptoms, IMMEDIATELY STOP the drug and take your dog to the vet. The earlier you catch the problem, the better the chances of complete recovery.
It will be helpful to Pfizer and may help to save your or another dog's life if you report any negative reactions your dog has or had when taking Rimadyl. You need only have a suspicion that Rimadyl is implicated. You may call Pfizer at 1-800-366-5288 and the FDA at: 1-888-332-8387 (or 1-888-FDA-VETS)