POM-V Prescription Required

Onsior

Active ingredient: Robenacoxib

COX-2 selective NSAID tablet for dogs and cats. Used for chronic osteoarthritis pain and post-operative pain.

Form

Tablet

Strength

5mg to 40mg

Species

Dog Cat

What it's used for

For the treatment of pain and inflammation associated with soft tissue surgery.

Full indications, dosage and side effects ↓

The prescription itself has a price. See what practices near you charge for a consultation and the written prescription fee.

Paying less for Robenacoxib

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

Fill it at a registered online retailer

The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

Your prescription rights → VMD register of retailers →

Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Onsior — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 27 Mar 2026.

For the treatment of pain and inflammation associated with soft tissue surgery.

Do not administer with food since clinical trials demonstrated better efficacy of
robenacoxib for osteoarthritis when administered without food or at least 30 minutes
before or after a meal.
Tablets are flavoured. The tablets should not be divided or broken.
Osteoarthritis: The recommended dose of robenacoxib is 1 mg/kg body weight with
a range 1–2 mg/kg. Administer once daily at the same time every day according to
the table below.
Number of Tablets by Strength and Body Weight for Osteoarthritis
Number of Tablets by StrengthBody Weight
(kg)
5 mg10 mg20 mg40 mg2.5 to < 51 tablet5 to < 101 tablet10 to < 201 tablet20 to < 401 tablet40 to 802 tablets
A clinical response is normally seen within a week. Treatment should be discontinued
after 10 days if no clinical improvement is apparent.
For long-term treatment, once a clinical response has been observed, the dose of
robenacoxib can be adjusted to the lowest effective individual dose reflecting that the
degree of pain and inflammation associated with chronic osteoarthritis may vary over
time. Regular monitoring should be undertaken by the veterinarian.
Soft tissue surgery: The recommended dose of robenacoxib is 2 mg/kg body
weight with a range of 2-4 mg/kg. Give as a single oral treatment prior to soft tissue
surgery.
The tablet(s) should be administered without food at least 30 minutes prior to
surgery.
After surgery, once daily treatment may be continued for up to two further days.
Number of Tablets by Strength and Body Weight for Soft Tissue Surgery
Number of Tablets by StrengthBody Weight
(kg)
5 mg10 mg20 mg40 mg2.5 1 tablet> 2.5 to < 5 1 tablet5 to < 101 tablet10 to < 201 tablet20 to < 402 tablets40 to < 603 tablets60 to 804 tablets

Do not use in dogs suffering from gastrointestinal ulceration or with hepatic disease.
Do not use concomitantly with corticosteroids or other non-steroidal anti-inflammatory
drugs (NSAIDs).
Do not use in cases of hypersensitivity to the active substance or to any of the
excipients.
Do not use in pregnant and lactating animals (see section 3.7).

Dogs:
Very common
(>1 animal / 10 animals
treated):
Gastrointestinal adverse events.
Vomiting, loose stool.
Common
(1 to 10 animals / 100 animals
treated):
Decreased appetite.
Diarrhoea.
Elevated liver enzymes.
Uncommon
(1 to 10 animals / 1,000
animals treated):
Blood in faeces
, vomiting
.
Anorexia, apathy.
Very rare
(<1 animal / 10,000 animals
treated, including isolated
reports):
Lethargy.
Most cases were mild and recovered without treatment.
In dogs treated up to 2 weeks no increases in liver enzyme activities were
observed. However, with long-term treatment, increases in liver enzyme activities
were common. In most cases there were no clinical signs and the liver enzyme
activities either stabilised or decreased with continued treatment.
Clinical signs associated with increases in liver enzyme activities.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder the national competent authority via the
national reporting system. See the package leaflet for respective contact details.

In clinical studies in dogs with osteoarthritis, inadequate response to treatment was
seen in 10-15% of the dogs.

Special precautions for safe use in the target species:
The safety of the veterinary medicinal product has not been established in dogs
weighing less than 2.5 kg or under 3 months of age.
For long term therapy, liver enzymes should be monitored at the start of therapy, e.g.
after 2, 4 and 8 weeks. Thereafter it is recommended to continue regular monitoring,
e.g. every 3-6 months. Therapy should be discontinued if liver enzyme activities
increase markedly or the dog shows clinical signs such as anorexia, apathy or
vomiting in combination with elevated liver enzymes.
Use in dogs with impaired cardiac or renal function or dogs that are dehydrated,
hypovolaemic or hypotensive may involve additional risks. If use cannot be avoided,
these dogs require careful monitoring.
Use this product under strict veterinary monitoring in dogs with a risk of
gastrointestinal ulcers, or if the dog previously displayed intolerance to other NSAIDs.
Tablets are flavoured. In order to avoid any accidental ingestion, store tablets out of
reach of the animals.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
For pregnant women, particularly near-term pregnant women, prolonged dermal
exposure increases the risk of premature closure of the ductus arteriosus in the
foetus. Pregnant women should take special care to avoid accidental exposure.
Accidental ingestion increases the risk for NSAID adverse effects, particularly in
small children. Care should be taken to avoid accidental ingestion by children. In
order to prevent children from accessing the product, do not remove tablets from the
blister until ready to administer to the animal. Tablets should be administered and
stored (in the original packaging) out of sight and reach of children.
In case of accidental ingestion, seek medical advice immediately and show the
package leaflet or the label to the physician.
Wash hands after use of the veterinary medicinal product.
Special precautions for the protection of the environment:
Not applicable.

Robenacoxib must not be administered in conjunction with other NSAIDs or
glucocorticoids. Pre-treatment with other anti-inflammatory medicines may result in
additional or increased adverse effects and accordingly a treatment-free period with
such substances should be observed for at least 24 hours before the commencement
of treatment with robenacoxib. The treatment-free period, however, should take into
account the pharmacokinetic properties of the products used previously.
Concomitant treatment with medicines displaying action on renal flow, e.g. diuretics
or angiotensin-converting enzyme (ACE) inhibitors, should be subject to clinical
monitoring. In healthy dogs treated with and without the diuretic furosemide,
concomitant administration of robenacoxib with the ACE inhibitor benazepril for 7
days was not associated with any negative effects on urine aldosterone
concentrations, plasma renin activity or glomerular filtration rate. No safety data in
the target population and no efficacy data in general exist for the combined treatment
of robenacoxib and benazepril.
Concurrent administration of potentially nephrotoxic medicines should be avoided as
there might be an increased risk of renal toxicity.
Concurrent use of other active substances that have a high degree of protein binding
may compete with robenacoxib for binding and thus lead to toxic effects.

Do not store above 30 °C. Store in the original package in order to protect from
moisture.

Not applicable.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.