Application site reaction after Flumethrin + Imidacloprid (Seresto) in cats

187 reports to the FDA describe application site reaction in cats given Flumethrin + Imidacloprid. That is 28% of all reports for this medicine, compared with 8.1% across reports for all cat medicines, so it is reported unusually often with this medicine.

187Reports

61%Marked serious

27%Recovered

2.1%Died or euthanised

14 daysTypical onset

How soon it started

Same day

10 6.9%

1–2 days

12 8.3%

3–7 days

29 20%

1–4 weeks

44 31%

Over a month

49 34%

How the animals did

Recovered

50 27%

Still unwell when reported

37 20%

Died

1 0.5%

Euthanised

3 1.6%

Not known

96 51%

Problems reported at the same time

111 59%

86 46%

51 27%

26 14%

Skin rash or irritation

18 9.6%

No sign

16 8.6%

Lethargy

11 5.9%

Loss of appetite

11 5.9%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 application site reaction in cats?: 187 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 14 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).

Application site reaction with similar medicines

Application site reaction after Spinosad (Comfortis) 25 reports · 0.2% of its reports
Application site reaction after Nitenpyram (Capstar) 41 reports · 0.5% of its reports
Application site reaction after Imidacloprid + Moxidectin (Advantage Multi) 1,047 reports · 13% of its reports
Application site reaction after Imidacloprid + Pyriproxyfen 45 reports · 6.9% of its reports
Application site reaction after Fipronil + S-methoprene (Frontline Plus) 28 reports · 7.6% of its reports

All reported side effects of Flumethrin + Imidacloprid in cats · Medicines most reported with application site reaction