You save 60%

Onsior® Tablets for Dogs 40mg

In stock
  • £1.02 £2.59 Save £1.57 Single tablet
  • £30.60 £75.90 Save £45.30 30 tablets
SRP £2.59
Add to Favourites
Onsior for Dogs is for the treatment of acute pain and inflammation associated with musculo-skeletal disorders.
Read more

Delivery See details

Genuine UK Animal Medicine Fully accredited online Vet Pharmacy
Secure Checkout with
  • Product Details
  • Instructions
Product Details

This is a prescription item and will be sent once a valid prescription has been received and approved by our vet.

What is Onsior? 

Onsior for dogs is an anti-inflammatory medication meant for the treatment of pain and inflammation associated with chronic osteoarthritis as well as pain and inflammation caused by soft tissue surgery in dogs. One tablet a day has been shown to reduce pain and improve mobility. 

Please note, as Onsior is a prescription medication, we are only able to dispatch the amount of tablets and the dosage stated on your prescription, so be sure to order the correct product in the correct amount to avoid any delays in your order. 

How Does Onsior Work? 

The active ingredient in Onsior for dogs is robenacoxib, meaning it belongs to a class of medications known as non-steroidal anti-inflammatory drugs (NSAIDs). This ingredient blocks an enzyme called cyclooxygenase 2 which is involved in the production of prostaglandins which are involved in pain and inflammation. By blocking the production of this substance, Onsior is able to reduce the pain and inflammation caused by musculoskeletal disorders, surgery or osteoarthritis.

Onsior for dogs is a prescription medication and will only be sent once a valid prescription is received. If you would like advice on how to send your pet’s prescription to us, please read our prescriptions information page. 


It is available in
  • Single or packs of 30 tablets


  • Active Ingredient

How to Store Onsior 40mg for Dogs

All Onsior tablets are sealed in blister pack packaging and have a shelf life of 4 years when unopened. Onsior should be kept out of sight and reach of children and animals and not stored above  25 °C.

Any unused Onsior should be appropriately disposed of either through your vet or at a suitable Disposal Of Old Pharmaceuticals (DOOP) Bin. 

Administration Instructions:

Important Safety Information

Onsior for dogs should not be administered if your dog: 

  • Suffers from gastrointestinal ulceration or has a hepatic disease.
  • Is currently taking corticosteroids or other non-steroidal anti-inflammatory drugs (NSAIDs).
  • Has hypersensitivity to the active substance or to any of the excipients.
  • Is pregnant, lactating or used for breeding. 
  • Weighs less than 2.5 kg or is under 3 months of age.

Onsior 40mg tablets are intended for use in dogs only. If you are looking for similar medication for a cat, we suggest checking the page for Onsior for cats

Administering Onsior to your Dog

Onsior tablets for dogs should be administered orally and are palatable to most dogs. 

Onsior should not be given with food as clinical trials have demonstrated better efficacy of robenacoxib for osteoarthritis when administered without food or at least 30 minutes before or after a meal.

Do not break or divide Onsior tablets as this can impact their effectiveness. 

Please note that you should wash your hands after handling Onsior tablets and pregnant women are advised to be particularly careful to avoid dermal exposure. 


Q - What are the side effects of ONSIOR for dogs?

A - Gastrointestinal upset has been commonly reported when dogs are treated with Onsior, however these reactions are mild and generally improve without treatment. These reactions include: 

  • Vomiting 
  • Soft Faeces
  • Decreased appetite 
  • Diarrhoea
  • Blood in faeces

If you think your dog may be having an adverse reaction to taking Onsior, please contact your vet immediately for further advice. 

Q - Is Onsior safe for dogs?

A - While some side effects have been noted when treating dogs with Onsior, these reactions tend to be mild and dogs often recover on their own. If you are concerned about your dog reacting to Onsior, please speak with your vet for further advice. 

For long-term use, your dog’s liver enzymes should be monitored by your vet to ensure it is safe to continue using. 

Some animals are also at a higher risk when using Onsior. Please consult your vet before administering Onsior if your dog has any of the following.

  • Prone to gastrointestinal ulcers
  • Impaired cardiac function
  • Impaired renal function
  • Dehydration, hypotension or hypovolaemia
  • Is already on ACE inhibitors or diuretic medication 

Q - How long does it take Onsior for dogs to work? 

A - Once the dose has been consumed, you should begin to see a relief in your dogs symptoms within 1-2 hours with more clinical improvement to follow over the course of treatment. 

Ordering prescription medication is easy

Follow these simple steps

  1. Get a prescription from your vet
  2. Place your order with us
  3. Add a prescription and tell us about your pet
  4. Our vets will double-check your order & once approved, your order will be dispatched within 2 working days.
Learn more

Service Reviews