Itching after Flumethrin + Imidacloprid (Seresto) in dogs

The FDA has received 610 reports of itching in dogs after Flumethrin + Imidacloprid. That is 27% of all reports for this medicine, compared with 4.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

610Reports

28%Marked serious

15%Recovered

2.1%Died or euthanised

43 daysTypical onset

How soon it started

Same day

34 7.9%

1–2 days

35 8.1%

3–7 days

21 4.9%

1–4 weeks

86 20%

Over a month

256 59%

How the animals did

Recovered

93 15%

Recovered with lasting effects

1 0.2%

Still unwell when reported

147 24%

Died

6 1.0%

Euthanised

7 1.1%

Not known

356 58%

Problems reported at the same time

Didn't stop fleas

337 55%

Hair loss

77 13%

Skin rash or irritation

62 10%

Skin redness

55 9.0%

Application site reaction

48 7.9%

Behaviour change

47 7.7%

Vomiting

44 7.2%

Lethargy

42 6.9%

Age of the animals

Under 1 year

1–3 years

134

4–7 years

152

8–11 years

122

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 itching in dogs?: 610 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 43 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).

Itching with similar medicines

Itching after Spinosad (Comfortis) 3,874 reports · 6.8% of its reports
Itching after Lufenuron + Milbemycin Oxime (Sentinel) 1,223 reports · 4.7% of its reports
Itching after Imidacloprid + Moxidectin (Advantage Multi) 2,227 reports · 17% of its reports
Itching after Nitenpyram (Capstar) 1,450 reports · 13% of its reports
Itching after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 281 reports · 2.8% of its reports
Itching after Fipronil + S-methoprene (Frontline Plus) 330 reports · 11% of its reports
Itching after Imidacloprid 297 reports · 16% of its reports
Itching after Fipronil 138 reports · 9.8% of its reports
Itching after Lufenuron 178 reports · 17% of its reports
Itching after Imidacloprid + Permethrin + Pyriproxyfen 206 reports · 28% of its reports

All reported side effects of Flumethrin + Imidacloprid in dogs · Medicines most reported with itching