Death after Flumethrin + Imidacloprid (Seresto) in cats

32 reports to the FDA describe death in cats given Flumethrin + Imidacloprid. That is 4.7% of all reports for this medicine, compared with 8.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

32Reports
100%Marked serious
0.0%Recovered
100%Died or euthanised
20 daysTypical onset
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How soon it started

Same day
0 0.0%
1–2 days
1 3.8%
3–7 days
4 15%
1–4 weeks
11 42%
Over a month
10 38%

How the animals did

Died
21 66%
Euthanised
11 34%

Problems reported at the same time

Age of the animals

Under 1 year
1
1–3 years
11
4–7 years
6
8–11 years
6
12+ years
4

About this medicine

Imidacloprid kills fleas (spot-on or collar).

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

Questions owners ask

Can Flumethrin + Imidacloprid cause death in cats?
32 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 20 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).

Death with similar medicines

All reported side effects of Flumethrin + Imidacloprid in cats · Medicines most reported with death