Deracoxib

(for veterinary information only)

BRAND NAME: DERAMAXX

AVAILABLE IN      
25 mg, 75 mg & 100 mg
CHEWABLES        

BACKGROUND

Deracoxib is a member of the class of drugs known as NSAIDs (non-steroidal anti-inflammatory drugs), the same class as such common over-the-counter remedies as Advil (Ibuprofen), Aleve (Naproxen), Orudis (ketoprofen), and aspirin as well as more controversial prescription drug such as Celebrex (celecoxib) and Vioxx (rofecoxib). This class of drug is used for pain relief successfully in humans but the development of safe NSAIDs for dogs has only been recently achieved and continues to be problematic in the cat. With the possible exception of aspirin, none of the human drugs listed above can be safely used in pets.

The problem with NSAID use in pets has been unacceptable (even life-threatening) side effects. Problems have in the past been related to:

  • Stomach ulceration - even perforation and rupture of the stomach can occur. This is not only painful but life-threatening.
     
  • Platelet deactivation - platelets are the cells controlling the ability to clot blood and, as a general rule, it is preferable not to promote bleeding. We would prefer platelets to remain active and able to function should we need them.
     
  • Decreased blood supply to the kidney - this could tip a borderline patient in to kidney failure.

The veterinary profession has been in need of an NSAID that could effectively relieve pain without the above risks. In 1997, Pfizer Animal Health released carprofen for dogs in the U.S. as the answer to this need. Carprofen had been available in the U.K. since 1994 and has earned a reputation for effectiveness and safety.

This new plane of safety is made possible by new biochemical knowledge. Inflammatory biochemicals responsible for the pain and inflammation we want to allieviate are produced by an enzyme called “cyclo-oxygenase 2.” The goal is to inhibit this enzyme without inhibiting its counterpart “cyclo-oxygenase 1.” Cyclo-oxygenase 1, abbreviated COX-1, is what is called a “constituitive” enzyme. This means it is involved in producing regulatory biochemicals (called “prostaglandins”) which are important in maintaining the normal health and function of our bodies. We want to leave this enzyme alone. Cyclo-oxygenase 2, abbreviated COX-2, produces inflammation but also is important in regulating kidney blood flow and in some reproductive and central nervous system function. In the past, NSAIDs could not distinguish the COX enzymes; they inhibited them both. With the development of “COX preferential” and “COX selective” NSAIDs, we can inhibit COX-2 and leave COX-1 alone. The introduction of COX-2 preferential NSAIDs has reduced stomach and intestinal side effects by 50% in humans and has made FDA approval of certain NSAIDs possible for pets.

A COX-2 preferential NSAID inhibits COX-2 much more than COX-1. A COX-2 selective NSAID inhibits COX-2 only. Deracoxib is a member of the "coxib" class of NSAIDS and is a COX-2 selective NSAID.

HOW THIS MEDICATION IS USED

Deracoxib is used in the treatment of pain either for short term or long term use with different dosing schedules depending on how the drug is to be used.

Deracoxib is for dogs only. Do not use this medication in a cat. At this time long term use of NSAIDs in the cat is limited to meloxicam and is not approved by the FDA.

All NSAIDs, even the COX-2 selective ones, have some potential for reactions. Deracoxib would not be appropriate for a dog with kidney or liver disease so screening tests are needed and monitoring tests are recommended. A dog that is potentially a candidate for long term use of deracoxib should have a complete examination by the veterinarian, a screening blood panel to establish baseline biochemical values, and ideally some kind of recheck testing two weeks after starting deracoxib. This is because most adverse reactions, unusual as they may be, occur within this initial time frame and it is important that they be recognized before they get out of hand. After this initial period, complete blood panels should be screened every six months, an important step with any medication for long term use, not just the NSAIDs.

SIDE EFFECTS

The side effects of concern are the same with all NSAIDs regardless of their COX selectivity: stomach ulceration, loss of kidney function, and inappropriate bleeding. These are dependent on the dose of medication used and on risk factors of the host (for example: an aged pet may not efficiently clear a dose of medication from its body leading to stronger and longer activity of the drug). There is also a particular idiosyncratic reaction for NSAIDs which has received a great deal of press. An idiosyncratic reaction is one that is not dose-dependent nor predictable by any apparent host factor; it simply happens out of the blue. This particular idiosyncratic reaction is a liver toxicity which is rare enough that it did not show up in any of the initial 400 test subjects with carprofen, nor in the U.K. use of the carprofen and was not recognized until carprofen was used in over a million dogs in the U.S. after its release as the first NSAID. At first this reaction was considered to be only a carprofen problem but as time has passed and more dogs have been on NSAIDs it hasa been found that this reaction can occur with any NSAID. We will review this reaction below along with the other potential NSAID side effects.

  • In a study of 207 dogs, half received deracoxib and half received placebo. The incidence of vomiting after orthopedic surgery was approximately 10% in the deracoxib group and 6% in the placebo group. Similar results were obtained for incisional oozing.
     
  • If a patient has borderline kidney function, NSAIDs should not be used as they reduce blood flow through the kidneys. It is also important that NSAIDS not be given to dehydrated patients because of this potential side effect.
     
  • The Hepatopathy Side Effect (usually occurs within the first 3 weeks of use)
    An NSAID reaction that has received special attention is hepatopathy, a type of liver disease. Symptoms include nausea, appetite loss, and/or diarrhea as well as marked elevations (3-4 times higher than the normal range) in liver enzymes measured in the blood.

    Dogs with this syndrome show improvement with support 5 - 10 days after discontinuing carprofen. It is important that the NSAID be discontinued and the patient evaluated in the event of upset stomach signs in case of this syndrome. Even though this is a rare syndrome (one in 5000), it can become life-threatening if ignored. Appetite loss or other intestinal signs do not necessarily indicate a hepatopathy but since they might, it is important not to ignore these signs should they occur. There is no way to predict which dogs will experience this side effect.

The hepatopathy reaction usually occurs in the first 3 weeks
after starting the NSAID but could theoretically occur later.

  • All NSAIDs are removed from the body by the liver. If the patient’s liver is not working normally due to another disease or if the patient is taking other drugs that are also removed by the liver, it is possible to “over work” the liver and exacerbate pre-existing liver disease. If there is any question about a patient’s liver function, another class of pain reliever should be selected.

It is important to realize that COX-selectivity is not the sole factor in safety. In humans, the incidence of kidney function-related side effects was unchanged by the development of COX-2 preferential NSAIDs and we expect the same is true with dogs. Still, these drugs have an excellent track record for safety. The important issue is to recognize risk factors for adverse reactions and take preventive steps (see the Concerns and Cautions section below). Many exaggerated reports and rumors have surfaced on the internet and it is important to consider only confirmed and properly investigated information.

INTERACTIONS WITH OTHER DRUGS

Drugs of the NSAID class should not be used concurrently as the potential for the aforementioned side effects increases. For similar reasons, NSAIDS should not be used in conjunction with corticosteroid hormones such as prednisone, dexamethasone, etc. Pfizer recommends a 5-7 day rest period when changing over to carprofen from one NSAID to another. Aspirin poses an exception due to its strong platelet inactivating abilities so 10-14 days is recommended when switching to carprofen from aspirin. Allow at least one week between prednisone and deracoxib.

If deracoxib is used concurrently with phenobarbital, it is especially important that appropriate liver monitoring be performed. (Our hospital recommends bile acids testing every 6 months for dogs on phenobarbital.) These two drugs interact such that neither may work well if they are used together.

ACE inhibitors such as enalapril or captopril may not be as effective in the presence of NSAIDs. (ACE inhibitors are used in the treatment of hypertension or heart failure.) This is because ACE inhibitors depend on the dilation of blood vessels in the kidneys and such dilation can be interfered with by NSAIDs).

Deracoxib is a member of a class of drugs called “sulfonamides” which means it contains a chemical group containing sulfur. Often these medications are called “sulfa drugs.” Antibiotics of the sulfa class (deracoxib is not an antibiotic) have been associated with some specific drug reactions (for more information see the section on trimethoprim sulfa). If a patient is known to have reactions against another sulfa drug, it is best to choose an NSAID other than deracoxib.

CONCERNS AND CAUTIONS

Deracoxib is available as a chewable tablet which is highly palatable to animals. This increases the potential for accidental overdose should a pet gain access to a large amount of chewable tablets.

Keep chewable deracoxib out of the reach of children and pets.

Deracoxib has not been tested in pregnant or nursing females and thus is not recommended for use in such individuals, particularly since COX-2 is important in reproductive function. This also means that pregnant women might do well not handling this medication.

NSAIDs should not be used in dogs with pre-existing liver or kidney disease. In order to screen for pre-existing liver or kidney disease it is a good idea to run a blood chemistry panel prior to starting long term therapy with an NSAID.

ANY DOG ON LONG TERM MEDICATION OF ANY KIND SHOULD
PROBABLY HAVE BLOOD CHEMISTRY RECHECKS EVERY 6 MONTHS.

The blood pressure related side effects that have made COX-2 selective NSAIDs
controversial in humans are not significant factors in canine use.

Deracoxib should not be used in patients with pre-existing GI ulcerations.

Deracoxib has been tested for safety in puppies as young as 4 months of age but not younger. Safety has not been evaluated in younger puppies.

To read the product insert for Deracoxib, click here:

www.deramaxx.com/content/Clinic_Insert.pdf

For more information on this product, visit:

www.deramaxx.com

Page last updated: 6/5/2011