Medication - Rimadyl


Warning:  Rimadyl will cause liver damage in some dogs. There have been some deaths in dogs with this reaction. This effects 0.02% of dogs and 70% of those are geriatric. More information can be found by consulting the Small Animal Clinics of Pharmacology's latest edition.. This is a remarkable drug for many dogs. Blood work however should be done prior to beginning treatment and one or two weeks into treatment  to monitor liver values.


Liver Values - Rimadyl

Q: Dear Dr. Michael Richards;    I have had a very confusing recent event regarding my 13 yr. old female dog  come up and I will include the blood analysis for your evaluation also. First;  my dog, Kahlua, is 13 yr. old, a little stiff due to old injury and arthritis. She eats very well, never vomits, no diarrea, norm stools.  She plays in the evenings with us,and  takes short walks during the day in her field.  I placed her on Rimadyl a few months ago to help with her discomfort due to the arthritis.  I took her to my vet to see if we should continue with the Rimadyl, and to have her checked.  He also did blood work as he said she has not had any in a while.  I also had them repeated on another visit.  I will give you both results. May 18th test results;   ALB = 4.29g/dl , ALKP = 867 U/L , ALT = 1095 U/L, (A DILUTION OF 1:1), CHOL = 520 mg/dl,  GLU =126.7 mg/dl, Ca =12.24 mg/dl, K = 5.73, TBIL = .83 mg/dl.  Bile acids; 18.l umol/L and bile acids post =31.2. Lipemia 2+.

May 29th test results;  AlKP =1780 U/L, ALT =391 U/L, AST = 33 U/L, CHOL =575MG/DL, CALCIUM =11.7MG/DL, AMYLASE =1337 U/L, GGTP = 32, Platelet Count = 482, Tot. Protein = 7.4G/DL, Tbil = .1, K = 5.5 MEQ/L.      I also had an ultrasound done and it was inconclusive as to what this might be.  They did not several lesions, and suggested a biopsy. My question to the vet was to my concern about the Rimadyl and it's involvement-she stated that it only affects acutely in the first two weeks of treatment. I also have stopped the Rimadyl after the May 18th test.  After the May 29th test- I have put her on Milk thistle 70G, Low Protein,Low Salt dry food, give Etogesic 300 mg 1 x day, give promethazine 1 x day, and also give her rec dosage of Hip Health-Glucosomine 1000mg+vit c 100mg.     What do I do next?  I am thinking of repeating the test with a question of bile duct blockage-she licks alot but had her anal glands removed years ago, and would also like to know if it sounds like I'm on the right track as far as meds and food go also.     Again, she is not showing any symptoms of being ill at all.  How can all this be happening and she is fine??                 Thanks so much,   Karen  

A: Karen-

The reactions to carprofen (Rimadyl Rx) that have been confirmed do seem to show up most frequently in the first few days to weeks of treatment. Despite that, I'd still be suspicious if a pet of mine had high liver enzyme levels and then I discontinued Rimadyl and the liver values improved. Since this is what happened to Kahlua, your suspicions seem reasonable to me --- just not certain.

We have seen several patients with sudden onset of illness in which the liver enzymes were elevated but later returned to normal (within a few weeks), or got close to normal, without us ever being able to figure out what happened. Most of these dogs have gone on to do fine despite the lack of a diagnosis. Since things are improving and since Kahlua feels OK, I don't see a problem with rechecking the liver values in a few days to a week or so and then basing the next diagnostic and treatment decisions on whether the enzyme levels continue to improve.

The calcium level on the first test was high enough to be worrisome. Hypercalcemia can indicate that neoplastic (malignant) cancer is present. Since it came down in the subsequent test this is less worrisome.  It might still be worth carefully examining her lymph nodes for enlargement and rechecking the calcium level along with the liver enzymes.

With alkaline phosphatase levels in the 600 to 1000 range in an older dog, I always worry about the possibility of Cushing's disease (hyperadrenocorticism). This disorder sometimes causes elevations in cholesterol levels, too. Usually there is increased drinking and urinating associated with this problem but not always.

Your impression of how Kahlua feels is pretty important. In general, it is OK to be a little more cautious and take some time re-evaluating lab work when a patient is eating well and feels well. Our experience has been that a lot of the time these dogs are "telling" you the truth --- they are OK.

Mike Richards, DVM


Medication side effects  - Rimadyl (Carprofen) and injectable Cartrophen

Q: Hi,   I read with HORROR your information on  arthritis medication.

1) Cartrophen is an AUSTRALIAN product made by  Biopharm in Bondi, Sydney.

2) Cartrophen given every 6 months is useless  according to Biopharm itself. The RECOMMENDED dosage for arthritic dogs is,  initially, 1 shot every week for 4 weeks then 1 shot every 4 weeks thereafter  for the dog's life. Biopharm say that the effects of Cartrophen MAY last,  depending on the dog, for up to 3 months but anything over is just a waste of  time for the owner and a waste of money. I have had my Chow on Cartrophen for almost 3 years and she has gone from a whimpering mess with pronounced arthritic  wear noticeable in a finger probe examination and also by X-ray to a happy dog  running about and playing with my other Chow and her arthritis reduced to the  point where you cannot notice it by finger probe - even the VET cannot find it  anymore. Cartrophen is currently undergoing FDA approval and has been undergoing  same since July 98. It is expected that by July 2000, it should be a legally  available drug in USA. It currently IS a legally available drug in many  countries, Canada included.

 3) Rimadyl is an NSAID and as any vet with  common sense and any human doctor will tell you, NSAIDs can be dangerous to  LETHAL for susceptible dogs or humans. As such, Rimadyl has been the cause of  the deaths of many dogs in USA and I refer you to for details of same. Recommending it without thought to that is not only dangerous for the dog but  should there be an owner willing to SUE over your advice then the court aspect  of it is dangerous to YOU. So far there is no 100% sure way to know which dog is  susceptible and which isnt.   I hope that, in future, you take the above into  account when issuing information to people who write in and hope that you  forward my Cartrophen information on to the person who asked you about it with  the old Chow.

Chow Addiction Society Founder and Lifetime  Member #1  

A: Chows-

Almost every medication that is used in veterinary medicine has the potential to cause side effects. Many of them have the potential to cause death as a side effect. The list of these medications is very long. Antibiotics often have the potential to cause injury or death. Vaccinations occasionally cause sickness or death. Anesthesia will occasionally cause serious problems, including death. Non-steroidal anti-inflammatory medications can also have detrimental effects. I have treated animals dying from the effects of herbal medications administered at home and have heard unconfirmed reports, similar to much of the information on the Senior Dog site, of problems associated with the use of injectable polyglycosamines, and it seems very likely based on the injection schedule provide that Cartrophen is a polyglycosamine product -- although I must emphasize that is just a guess.

While we do not specifically address this on the page on dog arthritis, we do have information on the effects of Rimadyl (Carprofen) on the web site in several places and it is possible to find this information using the search feature of the web site. I have asked Michal to move some of this information to the dog arthritis page.

The choice of medications to use in a particular patient should always involve an evaluation of the risk to the patient versus the expected benefit. Heartworm treatment medications cause death in 1 to 2% of patients - a far greater risk than most medications, but when the effects of not treating for heartworms are considered, this seems like a small risk. Carprofen provides many dogs with the ability to move comfortably for several months to even years beyond the time they would have been able to otherwise. I inform each of my clients of the potential risk of carprofen and some elect not to use it. Most clients recognize that the benefit outweighs the risk, especially when many are considering euthanasia as an alternative to allowing their pet to live in pain.

If Cartrophen is significantly better or just as good and safer than current medications, then it will be easy to recommend it when and if it is approved in the United States. In the meantime, I am glad that Rimadyl(carprofen) is available for my patients who need to be relieved of chronic pain from arthritis right now.

Mike Richards, DVM


Rimadyl and liver problems

Q: I just recently located your web site and want to thank you for it. I also thought I'd pass on an experience with Rimadyl. I have a dobie/dane cross (12yrs.old). She is on Soloxine and phenobarb. I also had her on Rimadyl for one year. She suddenly developed vomiting, extremely dark urine, and depression. A liver profile showed very high levels in liver function. We took her off the Rimadyl, decreased her phenobarb, and gave her fluids subcue.for a week. She responded very well. Her liver tests 10 days later were greatly improved , and she is doing very well 6 months later.


A: Page-

Thank you for relating this experience. Phenobarbital will sometimes cause liver disease even after extended use and since Rimadyl can also have this effect I will have to remember to be cautious when using, or advising us, of Rimadyl in dogs on phenobarbital for seizure control. I am glad that withdrawal of the medication was helpful and that you were paying attention and brought the situation to the attention of your vet.

Mike Richards, DVM      

Rimadyl and liver problems in Labs

Q: Dr Mike, You might want to add to the "Rimadyl" section that liver tests and enzyme panels should be done prior to this administration.  Many dogs, especially labs, have died from Rimadyl. You should probably speak to Pfizer about this as it has appeared in many newsgroups for the past several months.  Apparently, many vets aren't aware of its life-threatening effect to labrador retrievers.

Thank you.  

A: William-

We have received a couple of emails recently regarding liver disorders following the use of carprofen (Rimadyl Rx). This is reported on our site under side effects of medications but we will add this note to the Rimadyl page.

At present it appears that Rimadyl will cause liver damage in some dogs. There have been some deaths in dogs with this reaction, although I think that the use of the word "many" is misleading. The predominant breed affected by this reaction has been the Labrador retriever but there are reports of other breeds being affected.

Rimadyl benefits a large number of dogs. It harms a small number of dogs. The harm appears to be reversible by withdrawal of the drug. With all medications it is extremely important to pay attention to any potential side effects. With Rimadyl it is very important to discontinue use of the medication if a dog exhibits a decrease in appetite, lethargy, depression or any other signs of illness after administration of the medication. This is not a medication like insulin, in which withdrawal is dangerous to the pet. If there is evidence of any undesirable side effects the best course of action is to stop administering Rimadyl and to contact your vet.

It is hard to argue against drawing blood and checking serum chemistry levels to check for pre-existing liver or kidney problems prior to using a new medication in any pet and especially in older pets. However, I think it is important to point out that the predictive value of this testing is not established and that if the reaction to Rimadyl is similar to reactions to other medications there will not be much predictive value in the lab work. Most of the reactions to other medications do not occur as the result of pre-existing liver disease but as the result of an inability of a particular dog's liver to process the medication. The lab work protects the pharmaceutical company against claims that the medication caused conditions that already existed, which is one of the reasons the tests are promoted. Diagnosing a pre-existing condition may also help prevent further damage to an already damaged organ by allowing appropriate adjustments in medication dosage or prompting a decision to use a different medication. These are the other reasons testing is suggested Still, there is a good chance that dogs who will react to Rimadyl will have normal serum chemistry values prior to treatment and lab work should not be viewed as a guarantee that problems will not occur. Ideally, lab work should be done prior to administration of the medication and one month afterwards. For families on a budget trying to help their pets the additional expense of lab work may be inhibiting. If I had to chose between checking lab values before administration and after one month, I'd chose the later time. If  the cost of lab work will keep an owner from using Rimadyl then I feel comfortable pointing out that it must be discontinued if signs of illness after its use occur and not running lab tests prior to use or after use.

Would I use Rimadyl in my own dogs? Yes. In fact, I have done so. Do I worry about toxic effects? Of course I do. I watch my dogs carefully when adminstering any medication to see if there are changes that might be associated with the medication. Every dog owner should do this. Every vet should listen to dog owners and take their worries seriously after administration of a new medication. In many cases there are alternative medications that can be used or it may be reasonable to discontinue a medication for a condition that does not absolutely require it.

Rimadyl is a very effective medication for dogs with debilitating joint disease. It provides a measure of comfort to these pets that is worth taking some risk to provide, because it is more effective than any other non-steroidal medication I am aware of.  It can cause liver damage in a small percentage of the dogs it is given to. It is important to be aware of this problem and I am glad that people are aware of it. But it is just a risk to be considered, not a reason not to use Rimadyl when there is justification to do so.

Mike Richards, DVM      

Rimadyl (Rx)

Rimadyl (Rx) was recently approved for use in dogs in the United States. It has been available in other countries for some time. It is reported to be much less likely to cause gastrointestinal upset and kidney damage than older non-steroidal anti-inflammatory (NSAID) medications such as aspirin or phenylbutazone. It is reported to be very effective in conversations on the veterinary mailing lists and bulletin boards. With all new medications there is a period of time when everyone is worried that an unforseen side effect may occur. The U.S. is a huge market compared to other countries and the really rare problems tend to show up faster here than in smaller markets. The presently available data suggests that this is a safer and possibly more effective treatment than other NSAID medications, though.  

Mike Richards, DVM    

Rimadyl treatment

Q: My Chow started limping suddenly and was diagnosed with an arthritic hip in Feb., just a few months before she turned 7. She was placed on Rimadyl (75mg. 2x per day) for one week and the limping vanished. I then started her on a glucosamine/chondroitin and vitamin program. She was great until about 2 weeks ago when the limp returned. I then started her on Rimadyl once more, and again, all's well. Do I keep her on this product continuously, when necessary, or what? My own vet said to play it by ear...? Any suggestions? Another Vet I spoke with said to saturate her with Rimadyl for about ten days and then keep her on half the dosage alone or in conjunction with the above vitamins. Thanks for any light you can shed. J.

A: J- Rimadyl (Rx) can be used continuously. I do not know how well it works at lower than recommended dosages. The effectiveness of this sort of treatment varies a lot among pain relief medications and it is just too soon to have an idea how that will work with Rimadyl. I don't think it would hurt to try this approach if you are inclined to do so. Personally, I agree with your vet, though. I'd use the glycosamine product if it seems to help as the continous product and use Rimadyl as necessary for more severe pain. If and when it seems necessary to use Rimadyl continuously I would not hesitate to do so.

Mike Richards, DVM


Rimadyl and neurologic problems

Q: I have a 14 1/2 year old American Eskimo. She has arthritis and also had a mammory tummor 2 years ago. My vet prescribed Rimadyl for my dog after many other drugs failed. She was on Rimadyl for approximately 6 weeks and it seemed to make her back end just like rubber. She could not control her back lets to walk, and I had to create a "sling" to help her walk. My vet put her on 1/2 dosage 25 mg. and that seemed to give her more control, but not enough. Actually, she is now on Arthricare and seems to be having more control of her back end. Everyone keeps telling me how good Rimadyl is, and I was only one of 2 people at my vet's office that did not like the drug for my dog. Am I the only one that didn't get good results?

A: Kevin- Rimadyl (Rx) works for approximately 80% of the dogs it is prescribed for, based on the package insert information. I think that is about how well it has worked in our practice, too. For some dogs it really qualifies as a "miracle drug" and for others it has not beneficial effect. Except for one dog that vomited when Rimadyl was administered we have not had the experience of it making a problem worse or even causing problems unrelated to the what we were using it for. This is my theory and I am not sure it is accurate but I think that the dogs in which Rimadyl doesn't work well may have neurologic problems in many cases instead of arthritis. Confirming that arthritis is actually the cause of a dog's problems seems worthwhile when Rimadyl won't work, to me.

Mike Richards, DVM


Carprofen and other NSAIDS

Q: My question deals with Carprofen. Is there any information which compares equivalency to other NSAIDS. Are there other NSAIDS in the class such as ibu and keto profen which are also effective and save in dogs? Can you recommend some literature on this subject? Thank you for your help

A: I have not seen an equivalency chart for NSAIDS similar to the ones published for corticosteroids and opiates. If I run across one, I'll try to remember to put the information it contains online. Carprofen (Rimadyl Rx) is supposed to be a more potent pain-reliever and a slightly less potent anti-inflammatory than the other NSAIDS which are approved for dogs.

Ibuprofen and ketoprofen have both been implicated in gastric ulcer formation in dogs. These medications are supposed to be able to cause ulcers in most dogs with just a few days dosage (5 days to a week). There are occaional reports of ulceration with just one or two doses. Therefore, they are not commonly used in veterinary medicine. Indomethacin (Indocin Rx) also has a strong tendency to cause ulcers in dogs.

I have a few clients who report that they have used ibuprofen without problems but I have also treated two dogs for severe ulcers associated with this medication so my clinical experience comes close to matching the literature reports.

Mike Richards, DVM


Rimadyl - Cost a problem

Q: A friend of mine has asked me to find out more about Rimadyl. She has a dog with arthitis and has recently been prescibed that drug. It is a large dog and she is finding the price prohibitive. Is there any way to get the drug at a more cost-effient manner? At the moment it is costing her about $1 a pill. Please send me info on the drug and any sugestions on how to get it at a more reasonable price. By the way she is very pleased with the results, the dog is obviously much more comfortable.(the dog is an older dog) Thank you. Great column!

A: Carprofen (Rimadyl Rx) was just approved in this country. It will not be available generically for a long time so the price is likely to stay in the range you quoted for some time. If carprofen works as well as we hope it will, perhaps there may a drop in price as more of the medication is used, but that wouldn't be predictable. Your friend's vet might be willing to consider giving your friend a discount for a quantity purchase or something like that but I don't think it will bring the price down more than 10% or so.

It is acceptable to use aspirin long term in most dogs. It is more likely to cause gastrointestinal upset and stomach ulcers than carprofen but if these effects do not occur with use, it is much less expensive. This is an alternative when cost is a major factor in selection of an anti-inflammatory medication.

 Mike Richards, DVM


Rimadyl (Rx) - Can it be purchased less expensively

Q: Do you know of a supplier where I can purchase the drug called Rimadyl in bulk? I have a basset (Hershey) who has been diagnosed with hip dysplasia and he seems to respond to this drug. I am wondering if there are other sources to purchase the drug from instead of through the Veterinarian.

A: I am not aware of anyone selling carprofen (Rimadyl Rx) in bulk at this time. It was recently approved for use and is still protected by the drug patent laws. During this time, the pharmaceutical companies try to recover the costs of development and make their profit while their rights to a medication are protected. It is unlikely that the price of Rimadyl will drop significantly during this time. It is a prescription medication, so you would need a prescription from your vet in order to purchase it.

Your best bet is to ask your vet if he or she will give you a break for purchasing the medication in larger quantities. It can't hurt to ask, as long as you do it nicely!

Mike Richards, DVM

Rimadyl - How soon will it work

Q: I have a 11 year old golden retriever who seems to have developed an arthritic condition in her right front leg. In an attempt to avoid putting her on Rimadyl my vet intially gave her a shot of cortisone & placed her an an. anti-inflamatory pill for 10 days. The initial results were remarkable for the first 4 days. By the 5th day the symptons seemed to return somewhat but she still was much better that before taking the medication. Once the medication ran how she seemed to hold steady for a few days but we decided to try the Rimadyl on 3/19/97. She has only been on it for about 24 hours but actually seems worse today. How soon will I be able to tell whether or not the Rimadyl will help ?

A: Carprofen (Rimadyl Rx) is a pretty new medication and we do not have a lot of experience with it. We have used it in a small number of dogs at this time. Our impression is that it works pretty well for most dogs, doesn't work for all dogs and that it can take 4 or 5 days to get a good idea of whether it will be beneficial. It is very unlikely to work as well as a cortisone injection but it is also less likely to cause adverse side effects with long term use.

Let your vet know that you think your dog is worse but do give Rimadyl a chance to work if your vet thinks this is going to be a chronic condition and agrees that it is a good idea.

Mike Richards, DVM  

Rimadyl interaction

Q: Hello, i am writing because my dog chances, 12, was placed on rimadyl for her arthritis, it has become worse, the vet suggested that on bad days i give her 3 pills of 750 mg. i noticed that she has been shaking with that dosage, is that just because the dosage it too high and she cannot handle it, or does she need to get used to it. also she is on other medication, she is on vasotec for a heart condition and i placed her on shark cartliage to fight cancer. is this too many drugs for her? lately, she has not wanted to eat so much either, is that from the rimadyl causing upset stomach? the vet recommended this dietary food called A/D (i believe). Is there anything more i can do for her. she seems to have alot of good days and she doesnt seem to be in pain, i just want her around as long as possible, if you can help me find the best route to keep her around without her being in pain, please let me know. thank you. m.

A: I think that you should call your vet and discuss this situation with him or her. While I am not sure that it is a bona fide concern in "real life" veterinary practice, carprofen (Rimadyl Rx) could possibly interfere with the action of the enalapril (Vasotec Rx, Enacard Rx). If this does happen and if there is sufficient interference to decrease the action of the enalapril, you may be seeing signs related to a decrease in its activity.

Gastric upset is less common with carprofen than with other non-steroidal anti-inflammatory medications but it still can occur.

Please call your vet and discuss your concerns. If your vet has any questions about the interaction of carprofen and enalapril, calling Pfizer (the manufacturer of Rimadyl) may help to clear them up.

Mike Richards, DVM  


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...