onsior™
(robenacoxib)
6 mg Tablets for Cats
For Oral Use In Cats Only
Information for Cat Owners – You should read this information before starting your cat on ONSIOR tablets.
What is ONSIOR?
ONSIOR (robenacoxib) is a prescription non-narcotic, non-steroidal anti-inflammatory (NSAID) of the coxib class. ONSIOR (robenacoxib) is for the control of postoperative pain and inflammation associated with orthopedic surgery (declaw), ovariohysterectomy (spay) and castration (neuter) in cats greater than or equal to 5.5 pounds (2.5 kg) and greater than or equal to 4 months of age; for a maximum of 3 days. Do not use in cats less than 5.5 lbs.
Your cat may have received one or more doses of ONSIOR tablets or injection in the hospital. Your cat should not receive more than one dose a day, for a maximum of 3 total doses. Follow the instructions given to you by your veterinarian.
This summary contains important information about ONSIOR but does not take the place of instructions from your veterinarian. Talk to your veterinarian if you do not understand any of this information or if you want to know more about ONSIOR for cats.
What kind of results can I expect when my cat takes ONSIOR for postoperative pain and inflammation?
ONSIOR may help your cat to recover more comfortably by controlling postoperative pain and inflammation following orthopedic (declaw), ovariohysterectomy (spay), or castration surgery (neuter).
- Control of postoperative pain and inflammation may vary from cat to cat.
- Administer ONSIOR tablets according to your veterinarian‘s directions, for a maximum of 3 days.
- Consult your veterinarian if your cat appears to be uncomfortable.
What cats should not take ONSIOR?
Your cat should not be given ONSIOR if s/he:
- Has had an allergic reaction to robenacoxib, the active ingredient in ONSIOR for cats
- Has had an allergic reaction (such as hives, facial swelling, or red or itchy skin) to aspirin or other NSAIDs
- Is less than 5.5 lbs or less than 4 months of age
- Has a loss of appetite/decreased appetite
- Has bloody stool or vomit
- Is presently taking aspirin, other NSAIDs, or corticosteroids
- Has a pre-existing kidney or liver condition
- Has any condition predisposing to dehydration
ONSIOR tablets should only be given to cats.
People should not take ONSIOR tablets. Keep ONSIOR tablets and all medication out of reach of children. Call your physician immediately if you accidentally take ONSIOR tablets.
Tell your veterinarian about:
- Any side effects your cat has previously experienced from ONSIOR or other NSAIDs
- Any digestive upset (vomiting or diarrhea) your cat has had
- Any cardiovascular, kidney or liver disease your cat has had
- Any other medical problems or allergies that your cat has now or has had in the past
- All medications that you are giving your cat or plan to give your cat, including those you can get without prescription and any dietary supplements
- If you plan to breed your cat, or if your cat is pregnant or nursing
Talk to your veterinarian about:
- The surgery procedure performed on your cat
- What tests should be done before surgery and prior to administering ONSIOR
- The signs of postoperative pain or inflammation that may occur following surgery
- Normal events that can be expected after your cat undergoes surgery
- How often your cat may need to be examined by your veterinarian
- The risks and benefits of using ONSIOR
How to give ONSIOR tablets to your cat.
ONSIOR tablets should be given according to your veterinarian‘s instructions. Your veterinarian will tell you what amount of ONSIOR tablets is right for your cat. ONSIOR tablets should only be given once a day and for no longer than 3 days. ONSIOR tablets should not be broken. ONSIOR tablets should be given by mouth and may be given with or without food.
What are the possible side effects that may occur in my cat during therapy with ONSIOR tablets?
ONSIOR tablets may cause some side effects in individual cats. These are normally mild, but serious side effects have been reported in cats taking non-steroidal anti-inflammatory drugs (NSAIDs) including ONSIOR tablets. Serious side effects can result in death. It is important to stop the medication and contact your veterinarian immediately if you think your cat may have a medical problem or side effect while on ONSIOR tablets. If you have additional questions about possible side effects, talk with your veterinarian or call Elanco US Inc. at 1-888-545-5973.
Look for the possible following side effects that may indicate that your cat is having a problem:
- Decrease in appetite
- Vomiting
- Change in bowel movements such as diarrhea or change in stool color
- Change in drinking or urination
- Change in behavior, such as depression or restlessness
If any of the above signs are noticed in your cat, stop administering ONSIOR tablets and call your veterinarian.
Can ONSIOR tablets be given with other medications?
ONSIOR tablets should not be given with other non-steroidal anti-inflammatory drugs (NSAIDs – i.e. aspirin, meloxicam) or corticosteroids (i.e. prednisone).
Always tell your veterinarian about all medications that you have given your cat in the past, and any medications that you are planning to give with ONSIOR tablets.
What can I do in case my cat eats more than the prescribed amount of ONSIOR tablets?
Contact your veterinarian immediately if your cat eats more than the prescribed amount of ONSIOR tablets.
What else should I know about ONSIOR tablets?
This sheet provides a summary of information about ONSIOR tablets.
If you have any questions or concerns about ONSIOR or postoperative pain and inflammation, talk to your veterinarian.
As with all prescribed medications, ONSIOR tablets should only be given to the cat for which they are prescribed. They should be given to your cat only for the condition for which they were prescribed, at the prescribed dose, as directed by your veterinarian.
Approved by FDA under NADA # 141-320
Onsior, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates.
© 2026 Elanco or its affiliates
Revised: February 2026
ElancoTM
PA243561A 100294/100475