Onsior for Dogs - Robenacoxib Uses and Dosage

María Besteiros
By María Besteiros, Expert veterinary assistant and canine/feline hairdresser.. Updated: February 28, 2024
Onsior for Dogs - Robenacoxib Uses and Dosage

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Onsior is an anti-inflammatory analgesic medication which is used to alleviate pain and inflammation. It is from the coxib family of medications, a type of non-steroidal anti-inflammatory (NSAID), also known as a COX-2 inhibitor. While we commonly know it as Onsior, this is a trade name for the drug which has the active ingredient robenacoxib. Veterinarians usually prescribe it for chronic inflammatory processes such as osteoarthritis. Unlike many NSAIDs, Onsior can be administered over a long time, although it will always need to be monitored for side effects.

At AnimalWised, we look at Onsior for dogs and discover the uses, dosage and side effects of robenacoxib. It is important to note it is only available on prescription, so only a qualified veterinarian should prescribe this drug for your canine.

You may also be interested in: What is Onsior For Cats?


  1. What is Onsior for dogs?
  2. Uses of Onsior for dogs
  3. Onsior dosage for dogs
  4. Contraindications of Onsior for dogs
  5. Side effects of Onsior for dogs

What is Onsior for dogs?

The active substance in Onsior is robenacoxib , a member of the coxib family. It is a non-steroidal anti-inflammatory and antirheumatic with high affinity for COX-2. This means it inhibits the enzyme cyclooxygenase 2, an enzyme involved in a series of reactions that cause pain, inflammation or fever. It is for this reason the inhibitory effect of robenacoxib acts on inflammation and pain.

Onsior for dogs rapidly reaches high concentrations in the blood, is metabolized in the liver and is excreted via the bile and kidneys. Onsior is sold under the following preparations:

  • Tablets: usually round and flavored for easy ingestion.
  • Injectable solution: usually only to be administered clinically.

The flavoring of the tablets is usually so palatable to dogs they will enjoy them as if they were a treat. The tablets are usually not designed to be divided and must be given whole. Unlike many of the medications we discuss, Onsior is not a human medication we sometimes give to dogs. Although suitable for canine, feline and other veterinary uses, it should never be ingested by humans.

Onsior for Dogs - Robenacoxib Uses and Dosage - What is Onsior for dogs?

Uses of Onsior for dogs

Onsior for dogs is used to treat pain and inflammation in dogs suffering from chronic conditions such as osteoarthritis. These are characterized by lameness and require long-term treatment, although the improvement in the dog's condition can be seen in approximately one week. Generally speaking the types of painful inflammation in dogs include:

  • Musculoskeletal: including joint disorders such as arthritis in dogs.

  • Soft tissue: any soft tissue can become inflamed due to infections, trauma or other causes. Learn more with our article on why a dog has a swollen ear.

  • Gastrointestinal: although the gastrointestinal tract is largely made up of soft tissue, it is particularly prone to inflammation. These issues include inflammatory bowel disease in dogs, colitis and other problems which may be treated by Onsior.

  • Postoperative: Onsior is an anti-inflammatory which can be used after surgical intervention, including routine procedures such as spaying and neutering.

Onsior does not work for all inflammatory problems, so its use is at the veterinarian's discretion. If the dog does not improve after 10 days of treatment, administration should be stopped and the situation reassessed. Onsior can be administered for a prolonged period of time, but the veterinarian will know if it is suitable.

Onsior dosage for dogs

For the correct dosage, the weight of the dog and the reason it is prescribed must be taken into account. Only the veterinarian can prescribe this drug, as well as decide the dosage. A general guideline of Onsior administration is is 1 mg per kg of the dog's weight, although the veterinarian may consider it appropriate to increase it to 2 mg. Once the dog has stabilized, it should be maintained at the lowest possible dose. This will require regular veterinary checkups.

Onsior is intended to medicate the dog once a day, preferably at the same time every day. The tablets should not be given with food as ingestion with food decreases their effectiveness. They should be given a minimum of a half hour before or after eating.

When Onsior is given for an operation, the recommended oral dose is 2 mg per kg of weight. It can go up to 4 mg at the veterinarian's discretion. It is administered approximately half an hour before entering the operating room, usually in an injectable form. It can be continued for two days after the intervention.

Contraindications of Onsior for dogs

Onsior is not suitable for all dogs. The following contraindications need to be taken into account:

  • Dogs that have been diagnosed with a gastrointestinal ulcer or liver disease.

  • Care must also be taken with dogs with heart or kidney failure. Also with dehydrated, hypotensive dogs, as well as dogs that have lost a large amount of blood.

  • Female dogs that are pregnant or lactating should also not take Onsior. There is no evidence of its safety.

  • It is not recommended for dogs weighing less than 2.5 kg or less than three months of age, since there are no studies on the safety of the drug in these cases.

  • If our dog is already taking glucocorticoids or other non-steroidal anti-inflammatory drugs the veterinarian must be notified. In most cases, Onsior is not recommended. Simultaneous use of these drugs can cause or increase adverse effects. If the dog is taking corticosteroids or NSAIDs and you want to switch to Onsior, the medication should be stopped at least 24 hours before starting the new treatment, although the recommended time will depend on each drug.

  • Caution must be exercised if the dog is being treated with drugs that act on renal blood flow, such as benazepril, as there are no data on the safety of its joint administration.

  • If on some occasion the dog has shown an allergy to the active ingredient, do not give it Onsior.
Onsior for Dogs - Robenacoxib Uses and Dosage - Contraindications of Onsior for dogs

Side effects of Onsior for dogs

Treatment with Onsior for dogs is usually prolonged. It requires veterinary monitoring to control possible side effects. This means that the dog must have regular blood tests to monitor liver function. They should be performed frequently at approximately 2, 4, and 8 weeks. Once this first phase has passed, the controls can last up to 3-6 months. If any increase in liver enzymes or symptoms that may be related to their elevation are detected, the veterinarian will have to suspend the treatment. These symptoms include:

  • Loss of appetite
  • Apathy
  • Vomiting, nausea and diarrhea are mild but common side effects of Onsior
  • In a small percentage of cases, blood can be detected in the dog's stool
  • It is also common for liver enzymes to increase, without associated symptoms, when treatment is prolonged, although they usually stabilize and even decrease even if Onsior is continued
  • An overdose of Onsior can cause gastrointestinal, renal or hepatic alterations in the dog

If you notice any symptoms in your dog, you should go to the vet. There is no specific antidote for poisoning, but supportive therapy can be administered. If overdose occurs after subcutaneous injection of Onsior for dogs, edema, redness, thickening of the skin or a wound at the point of inoculation may occur, as well as gastrointestinal inflammation or bleeding.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Onsior for Dogs - Robenacoxib Uses and Dosage, we recommend you visit our Medicine category.

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Onsior for Dogs - Robenacoxib Uses and Dosage