Leucocytosis after Maropitant (Cerenia) in cats

The FDA has received 119 reports of leucocytosis in cats after Maropitant. That is 3.1% of all reports for this medicine, compared with 0.9% across reports for all cat medicines, so it is reported unusually often with this medicine.

119Reports

78%Marked serious

11%Recovered

42%Died or euthanised

2 daysTypical onset

How soon it started

Same day

34 33%

1–2 days

26 25%

3–7 days

15 15%

1–4 weeks

12 12%

Over a month

16 16%

How the animals did

Recovered

13 11%

Still unwell when reported

36 30%

Died

18 15%

Euthanised

32 27%

Not known

20 17%

Problems reported at the same time

77 65%

68 57%

50 42%

49 41%

48 40%

45 38%

42 35%

34 29%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Maropitant prevents vomiting and motion sickness.

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

Questions owners ask

Can Maropitant cause leucocytosis in cats?: 119 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).

Leucocytosis with similar medicines

Leucocytosis after Mirtazapine (Mirataz) 38 reports · 2.0% of its reports

All reported side effects of Maropitant in cats · Medicines most reported with leucocytosis