Decreased haematocrit after Ilunocitinib (Zenrelia) in dogs

The FDA has received 178 reports of decreased haematocrit in dogs after Ilunocitinib. That is 8.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

178Reports
33%Marked serious
9.6%Recovered
11%Died or euthanised
111 daysTypical onset
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How soon it started

Same day
4 2.9%
1–2 days
2 1.4%
3–7 days
3 2.2%
1–4 weeks
19 14%
Over a month
110 80%

How the animals did

Recovered
17 9.6%
Still unwell when reported
69 39%
Died
1 0.6%
Euthanised
18 10%
Not known
73 41%

Problems reported at the same time

Decreased red blood cell count
92 52%
Blood problems
75 42%
Decreased haemoglobin
72 40%
Eosinopenia
48 27%
Lymphopenia
47 26%
Lethargy
46 26%
Neutropenia
45 25%
Liver problems
44 25%

Age of the animals

Under 1 year
1
1–3 years
23
4–7 years
75
8–11 years
60
12+ years
13

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 decreased haematocrit in dogs?
178 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 111 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).

Decreased haematocrit with similar medicines

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