Leucocytosis after Mirtazapine (Mirataz) in dogs

The FDA has received 31 reports of leucocytosis in dogs after Mirtazapine. That is 11% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported unusually often with this medicine.

31Reports

87%Marked serious

3.2%Recovered

61%Died or euthanised

8 daysTypical onset

How soon it started

Same day

3 13%

1–2 days

5 21%

3–7 days

3 13%

1–4 weeks

9 38%

Over a month

4 17%

How the animals did

Recovered

1 3.2%

Still unwell when reported

10 32%

Died

2 6.5%

Euthanised

17 55%

Not known

1 3.2%

Problems reported at the same time

25 81%

21 68%

19 61%

18 58%

17 55%

17 55%

16 52%

13 42%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Mirtazapine stimulates appetite (cats: ointment applied to the ear).

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

Questions owners ask

Can Mirtazapine cause leucocytosis in dogs?: 31 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 8 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 Maropitant (Cerenia) 723 reports · 6.1% of its reports
Leucocytosis after Capromorelin (Entyce) 66 reports · 4.4% of its reports

All reported side effects of Mirtazapine in dogs · Medicines most reported with leucocytosis