Monocytosis after Ilunocitinib (Zenrelia) in dogs

The FDA has received 35 reports of monocytosis in dogs after Ilunocitinib. That is 1.6% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

35Reports

63%Marked serious

5.7%Recovered

20%Died or euthanised

132 daysTypical onset

How soon it started

Same day

1 4.0%

1–2 days

0 0.0%

3–7 days

3 12%

1–4 weeks

3 12%

Over a month

18 72%

How the animals did

Recovered

2 5.7%

Still unwell when reported

12 34%

Euthanised

7 20%

Not known

14 40%

Problems reported at the same time

Neutrophilia

18 51%

Lethargy

15 43%

Decreased haemoglobin

15 43%

Decreased haematocrit

15 43%

14 40%

13 37%

11 31%

10 29%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Ilunocitinib controls itching from allergies (tablet, a JAK inhibitor).

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

Questions owners ask

Can Ilunocitinib cause monocytosis in dogs?: 35 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 132 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).

Monocytosis with similar medicines

Monocytosis after Oclacitinib (Apoquel) 134 reports · 0.5% of its reports
Monocytosis after Cyclosporine (Atopica) 85 reports · 0.6% of its reports

All reported side effects of Ilunocitinib in dogs · Medicines most reported with monocytosis