By Lauren Forsythe, PharmD, DICVP; Rania Gollakner, BS DVM, MPH

What is robenacoxib?

Robenacoxib (brand name: Onsior®) is a nonsteroidal anti-inflammatory drug (NSAID) used to treat post-operative inflammation and pain in dogs and cats. It is also effective for treating pain and inflammation from other causes, such as musculoskeletal disorders.

In the US, the use of robenacoxib in cats and dogs to treat inflammation due to musculoskeletal disorders is “off label”. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as they may be significantly different from those on the label.

How do I give my pet robenacoxib?

  • Robenacoxib is available both as an oral tablet and a veterinarian-administered injection. 
  • Oral robenacoxib can be given with or without food; however, if vomiting occurs when dosed on an empty stomach, give future doses with food. 
  • In dogs, if vomiting occurs shortly after dosing, you can give another dose with food. 
  • The tablets should be given whole and are not designed to be broken.

Wash your hands after administering this medication. Pregnant women should wear gloves when handling this medication.

This medication will take effect quickly, in about one to two hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember. However, if it is close to the time for the next dose, skip the dose you missed, give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects from robenacoxib?

Like other NSAIDs, robenacoxib can  have side effects, including:

  • anorexia (lack of appetite)
  • lethargy
  • depression
  • vomiting
  • diarrhea
  • kidney disease and kidney failure
  • bleeding or infection at the surgical incision site is possible

SERIOUS ADVERSE REACTIONS ASSOCIATED WITH THIS DRUG MAY OCCUR WITHOUT WARNING AND COULD, IN RARE CASES, LEAD TO DEATH. If any of the following signs develop, stop giving robenacoxib and contact your veterinarian immediately:

  • yellowing of the skin or gums
  • changes in the frequency or amount of water consumption or urination
  • seizures
  • abnormal behavior
  • incoordination
  • weakness
  • severe vomiting or diarrhea 

NEVER give robenacoxib prescribed for one pet in your household to another pet without first consulting your veterinarian.

This moderate-acting medication should stop working in a few days, although the effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Robenacoxib SHOULD NOT BE USED in pets that:

  • are allergic to it or other NSAIDs
  • have gastrointestinal ulcers
  • are pregnant or nursing
  • are younger than four months old

Robenacoxib SHOULD BE USED WITH EXTREME CAUTION, or not at all, in pets that:

  • are dehydrated
  • are on diuretic therapy
  • have existing severe renal, heart, or liver disease

USE CAUTIOUSLY in dogs that are geriatric or have bleeding disorders.

Blood work should be performed prior to starting this medication to check for these risk factors. Your veterinarian can discuss risks specific to your pet.

Are there any drug interactions I should be aware of?

  • Avoid giving your pet other NSAIDs or corticosteroids (e.g., prednisone, dexamethasone) while they are taking robenacoxib.
  • Certain medications may interact with robenacoxib, so it is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your dog is taking before starting any new treatment.  Medications of concern include:
    • cyclosporine (Atopica®)
    • furosemide (Lasix®)
    • selective serotonin reuptake inhibitors (SSRIs) (e.g., fluoxetine [Reconcile®, Prozac®])
    • tricyclic antidepressants (e.g., amitriptyline [Elavil®], clomipramine [Clomicalm®])

Is any monitoring needed with this medication?

  • Your veterinarian should perform bloodwork and urinalysis before your pet starts robenacoxib, to screen for disease mentioned in risk factors, above, and to provide a baseline to compare to subsequent testing.
  • If your pet takes robenacoxib for extended periods (as in the treatment of osteoarthritis), your veterinarian will do periodic blood tests to check liver and kidney function. It is very important to attend these follow-up appointments. 
  • Your veterinarian may recommend recheck examinations to ensure the medication is working adequately to manage pain.
  • At home, monitor for any side effects such as those noted above. If any side effects occur, discontinue the medication and contact your veterinarian.  

How do I store robenacoxib?

  • Store the tablet form of this medication the blister pack at room temperature, between 59°F and 77°F (15°C and 25°C). 
  • Secure inside a cabinet to prevent accidental ingestion. These chewable tablets can be very tempting to dogs.
  • Keep the container out of reach of children and pets. 
  • Store compounded forms of this medication according to the label.

What should I do in case of an emergency?

If you suspect an overdose or adverse reaction to the medication, call your veterinarian immediately. If your veterinarian is not available, follow their directions in contacting an emergency facility. If your pet receives too much of this medication, it can have serious effects on the gastrointestinal system, liver, or kidneys.

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