Lymphopenia after Robenacoxib (Onsior) in cats

The FDA has received 58 reports of lymphopenia in cats after Robenacoxib. That is 1.8% of all reports for this medicine, compared with 0.4% across reports for all cat medicines, so it is reported unusually often with this medicine.

58Reports

83%Marked serious

22%Recovered

29%Died or euthanised

2 daysTypical onset

How soon it started

Same day

14 28%

1–2 days

20 40%

3–7 days

2 4.0%

1–4 weeks

11 22%

Over a month

3 6.0%

How the animals did

Recovered

13 22%

Still unwell when reported

23 40%

Died

7 12%

Euthanised

10 17%

Not known

5 8.6%

Problems reported at the same time

33 57%

32 55%

23 40%

20 34%

17 29%

16 28%

16 28%

16 28%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Robenacoxib relieves pain and inflammation (short courses).

Products with this ingredient include Onsior. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

NSAIDs can affect the stomach, liver and kidneys. Vets usually recommend blood tests before and during long-term use.

Questions owners ask

Can Robenacoxib cause lymphopenia in cats?: 58 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 2 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Lymphopenia with similar medicines

Lymphopenia after Meloxicam (Metacam) 42 reports · 1.1% of its reports

All reported side effects of Robenacoxib in cats · Medicines most reported with lymphopenia