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Pet Medication 101: Onsior

Onsior for dogs and cats

It’s important to understand a medication’s uses and side effects before giving it to your pet. This medication info sheet is meant to give you a good understanding of what Onsior (robenaxocib) is used for, how it works, and potential side effects in cats and dogs. Always consult a veterinarian before giving your pet any medication.

1. Drug Name:


2. Brand Name:


3. How Dispensed:


4. Forms:

5mg, 6mg, 10mg, 20mg, 40 mg tablets

20mg/mL injectable solution

5. Drug Type/Class:

Non-steroidal anti-inflammatory drug (NSAID)

6. Uses in Dogs and Cats:

Onsior is used to control pain and inflammation that is associated with surgery and musculoskeletal disorders such as osteoarthritis and fractures.

7. How it Works:

Robenacoxib blocks the enzyme (protein that increases the rate of a chemical reaction) cyclooxygenase (COX-2). Blocking this enzyme decreases the production of prostaglandins that causes the pain and swelling of inflammation and other conditions. Inhibiting COX-2 provides anti-inflammatory, pain relief, and can decrease fever.

8. Side Effects and/or Signs of Overdose:

Gastrointestinal side effects are common and can occur in 10% of dogs and cats. These side effects include vomiting, soft stool to diarrhea, decreased appetite, and blood in the stool. Some pets may have a decrease in energy levels. Elevated liver enzymes are common in dogs on long-term robenacoxib.

Overdosage can cause gastrointestinal upset and adverse effects on the kidney. Gastrointestinal ulceration can occur which can cause perforation (development of a hole) in the stomach or intestine. This can lead to infection and inflammation in the abdomen (peritonitis) or throughout the entire body (sepsis).

9. Drug Interactions:

  • Corticosteroids and other NSAIDs increase the risk of gastrointestinal toxicity
  • Aminoglycoside antibiotics (such as gentamicin or amikacin) may increase the risk of kidney toxicity
  • Furosemide
  • Cimetidine
  • Insulin may increase the risk of hypoglycemia
  • Cyclosporine
  • Methotrexate
  • Aspirin and clopidogrel increase the risk of bleeding

10. Cautionary Statements:

  • NSAIDs should only be used in animals that are otherwise healthy. Do not use in patients who are dehydrated or have impaired heart or kidney function
  • Animals should be closely monitored, and clients should be advised of the clinical signs of, side effects of NSAIDs
  • Risk factors for side effects include: disease of the liver, gastrointestinal tract, and kidney
  • Liver injury may occur with robenacoxib
  • Bloodwork is recommended before starting an NSAID and monitoring liver and kidney bloodwork if being used long term
  • Contraindicated in pregnant and lactating animals

Read more:

Signs of Pain in Dogs

Signs of Pain in Cats

Arthritis in Dogs

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