Whilst we remain operational and working really hard to take care of your pet's products as quickly as possible, there may be delays of up to 6 days longer than usual to process your order. Keep safe and stay healthy! You can read more about how we're doing here.
 4.8/5 on Trustpilot with 50k+ reviews!

Onsior for Dogs & Cats

Onsior for Dogs & Cats

Images are for illustration purposes only. Packaging may change from time to time and images on our website may or may not be updated.

  • Cat 6mg » Priced per Tablet £0.79
  • Dog 5mg » Priced per Tablet £0.59
  • Dog 10mg » Priced per Tablet £0.79
  • Dog 20mg » Priced per Tablet £1.09
  • Dog 40mg » Priced per Tablet £1.29
  • Solution for Injection » 20mg/ml £67.00

Selection of 6 products from

£0.59 to £67.00


Onsior is one of the safest medications of its type for use in dogs and cats. For dogs it is used primarily to treat osteoarthritis (degenerative joint disease). Onsior reduces pain and stiffness in the joints of affected dogs, increasing their mobility and enjoyment of exercise. Onsior can also be an effective treatment for the relief of pain and inflammation of other causes in both dogs and cats. Its effects are directed particularly at the causes of the inflammation meaning that side effects are much less likely to occur.

Onsior should not be given to patients which are dehydrated, or if underlying kidney or gastro-intestinal conditions might be present. Treatment should be supended if vomiting or diarrhoea are seen.

Need help or advice? Contact us:

  • Landline: 01582 842096
  • Mon - Fri: 8:00am - 6:00pm
  • Sat: 9:00am - 1:00pm
  • Email: [email protected]

All prices include VAT where applicable.

Medication Datasheets

Delivery Information

Reviews (51)

Summary of Reviews for Onsior for Dogs & Cats

Overall 5
Ease Of Use
Value For Money
Absence Of Side Effects
49 out of 51 (96%) customers would recommend this product.
5 stars (43 reviews)
4 stars (6 reviews)
3 stars (0 reviews)
2 stars (1 reviews)
1 stars (1 reviews)

Only verified purchasers of this product can leave a review.

55 Good product
Verified Purchase

By on 16 December 2019


Customer recommends this product

55 Onsior
Verified Purchase

By on 7 March 2019

Yes I really like this product. Buster is a bit of a devil when it comes to taking tablets, being able to hide them on his gum line to spit them out two hours later. These he seems to swallow before he has chance to hide them. They work well and he seems comfortable in himself.

Customer recommends this product

55 Onsoir for dogs
Verified Purchase

By on 2 January 2019

Have received them from our vetenary practice paying double the price that your company has them for,on asking for a repeat prescription vet informed us we were doing the right thing as they couldn't supply the med any cheaper

Customer recommends this product

55 It Works
Verified Purchase

By on 15 December 2018

Leo is so much better and loves his walks . And viovet are excellent they delivered in 2 Days

Customer recommends this product

55 Very effective from the first day for my dogs calcium deposits in his front paws.
Verified Purchase

By on 17 October 2018

All the other meds we tried for him made him really sick, often both ends. Onsior is well tolerated. He will not eat it's on own, so I mix it with food, which reduces it's absorption a bit, but I wouldn't say it reduced the efficacy at all.

Customer recommends this product

Page 1 of 11

Next Page

Q & A

Below are some recent questions we've received regarding Onsior for Dogs & Cats, including answers from our team.

13 July 2016 at 2:22pm

Onsior or Previcox

Cherry Welsh

  • VioVet customer since 2015
  • From: Argyll and Bute, United Kingdom

I would be grateful if you could tell me if there is any significant difference between these 2 drugs regarding their safety and effectiveness in treating osteoarthritis.

My dog had Onsior for a few weeks and it didn't seem to make much difference.

With thanks

  • VioVet Staff

These are both effective normally at reducing the discomfort from osteoarthritis. I am not aware of any scientific investigations conducted to try and compare them in this way, but they are both generally regarded as about equally safe and effective based on anecdotal evidence. Some dogs might happen to respond better to one drug than another, but I do not think that is particularly likely. I would have to question if the symptoms you are noticing are genuinely caused by the osteoarthritis which has been identified. Obviously I cannot tell and indeed it might be very difficult to be sure, but I would say that sometimes osteoarthritis can exist without causing obvious trouble for the dog. Another, unidentified condition could be causing trouble now, rather than the osteoarthritis. My first suggestion would be to re-evaluate the diagnosis, which obviously means going back to your vet. If nothing else is identified, then perhaps just try a different drug as well as doing all you can in other ways to help. Joint supplements such as Yumove or Joint Force are widely believed to be able to help. It is also helpful to encourage regular, gentle exercise (but never excited, strenuous or prolonged). Weight loss through food reduction is for some dogs the most beneficial thing you can do, but that depends on the current bodyweight and other factors. All else being equal though, you aim for a slim dog. It is always possible through simply giving less food, but that is very difficult for many people in practice.

19 December 2015 at 9:55am



Can this be given at the same time as yumove?

  • VioVet Staff

It is very common to use a prescription, anti-inflammatory drug such as Onsior along with a non-prescription, joint supplement such as Yumove. Many vets do recommend this and it is safe. Other measures can involve restricting food levels a bit to help keep body weight down as well as encouraging regular but gentle exercise.

21 April 2015 at 9:02pm

Onsior overdose?

Gilly Peters

Hector is on constant Onsior, 1 tablet per day, but today we both inadvertently dosed him, so he has taken 2. Could this be dangerous? He seems hyper and a bit "whiney" (He is a 30kg Lab/lurcher).

  • VioVet Staff

This is unlikely to cause trouble, but it certainly could. If your dog shows any vomiting or diarrhoea it is important not to give any more tablets and go straight to your vet. If he seems fine then all should be well. I would be tempted to miss out the next dose though.

23 February 2015 at 2:20pm

Extra Tablets


Hello there
My dog has just been diagnosed with Elbow Dysplasia and has been given these Onsior tablets (40mg) to take.
We was wondering if we can also give him some herbal tablets too, as we gave him them before and seemed to help him, however we do not want any weird side effects.
Thank you for your help
Deanna Miller

  • VioVet Staff

Most herbal tablets appear to be safe and can be given alongside Onsior, but they have not all been tested and there is no scientific confirmation of that initial comment. Personally I would be happy for you to give any of the main brand herbal products at the recommended amount alongside Onsior. As long as your dog is otherwise well, it is very unlikely that there would be any sort of adverse reaction.The glucosamine/chondroitin based supplements, such as Joint Force, are regarded as particularly suitable to add to the treatment.

6 May 2014 at 11:00pm

Hair loss


My dog has been taking on onsior and is doing her leg good, can you please tell me if it has any side effects as she is losing her coat, it started with a lilltle bald patch on her back but now it's coming out on her chest
Please help
Thank you

  • VioVet Staff

Onsior can occasionally have side effects, but hair loss is very unlikely to be due to the Onsior. It is much more likely to be a coincidence that the hair loss is occurring at the same time. I would make sure that your flea control measures are adequate, even if you see no fleas, and take your cat to the vet to be checked out for any other causes. (A flea allergy would be a very common cause for hair loss on cats, and can happen with very few fleas which are difficult to see.)