Vomiting after Flumethrin + Imidacloprid (Seresto) in cats

The FDA has received 59 reports of vomiting in cats after Flumethrin + Imidacloprid. That is 8.8% of all reports for this medicine, compared with 18% across reports for all cat medicines, so it is reported less often than average with this medicine.

59Reports

47%Marked serious

27%Recovered

8.5%Died or euthanised

13 daysTypical onset

How soon it started

Same day

7 15%

1–2 days

8 17%

3–7 days

6 13%

1–4 weeks

10 21%

Over a month

16 34%

How the animals did

Recovered

16 27%

Still unwell when reported

7 12%

Died

2 3.4%

Euthanised

3 5.1%

Not known

31 53%

Problems reported at the same time

21 36%

17 29%

15 25%

11 19%

Application site reaction

11 19%

Didn't stop fleas

11 19%

Weight loss

9 15%

Hair loss

7 12%

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 vomiting in cats?: 59 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 13 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).

Vomiting with similar medicines

Vomiting after Spinosad (Comfortis) 8,410 reports · 73% of its reports
Vomiting after Nitenpyram (Capstar) 630 reports · 7.2% of its reports
Vomiting after Imidacloprid + Moxidectin (Advantage Multi) 861 reports · 11% of its reports
Vomiting after Lufenuron 222 reports · 20% of its reports
Vomiting after Imidacloprid + Pyriproxyfen 68 reports · 10% of its reports
Vomiting after Fipronil 82 reports · 16% of its reports
Vomiting after Fipronil + S-methoprene (Frontline Plus) 54 reports · 15% of its reports
Vomiting after Imidacloprid 37 reports · 15% of its reports

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