Skin rash or irritation after Flumethrin + Imidacloprid (Seresto) in dogs

The FDA has received 103 reports of skin rash or irritation in dogs after Flumethrin + Imidacloprid. That is 4.5% of all reports for this medicine, compared with 1.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

103Reports

50%Marked serious

20%Recovered

2.9%Died or euthanised

44 daysTypical onset

How soon it started

Same day

10 13%

1–2 days

2 2.7%

3–7 days

3 4.0%

1–4 weeks

18 24%

Over a month

42 56%

How the animals did

Recovered

21 20%

Still unwell when reported

30 29%

Died

2 1.9%

Euthanised

1 1.0%

Not known

49 48%

Problems reported at the same time

Itching

62 60%

Didn't stop fleas

35 34%

Hair loss

24 23%

Application site reaction

21 20%

Skin redness

19 18%

Behaviour change

9 8.7%

Vomiting

9 8.7%

Didn't work as expected

7 6.8%

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 skin rash or irritation in dogs?: 103 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 44 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).

Skin rash or irritation with similar medicines

Skin rash or irritation after Spinosad (Comfortis) 726 reports · 1.3% of its reports
Skin rash or irritation after Lufenuron + Milbemycin Oxime (Sentinel) 344 reports · 1.3% of its reports
Skin rash or irritation after Imidacloprid + Moxidectin (Advantage Multi) 504 reports · 3.8% of its reports
Skin rash or irritation after Nitenpyram (Capstar) 163 reports · 1.5% of its reports
Skin rash or irritation after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 45 reports · 0.5% of its reports
Skin rash or irritation after Fipronil + S-methoprene (Frontline Plus) 62 reports · 2.1% of its reports
Skin rash or irritation after Imidacloprid 44 reports · 2.3% of its reports
Skin rash or irritation after Fipronil 30 reports · 2.1% of its reports
Skin rash or irritation after Lufenuron 60 reports · 5.9% of its reports
Skin rash or irritation after Imidacloprid + Permethrin + Pyriproxyfen 25 reports · 3.4% of its reports

All reported side effects of Flumethrin + Imidacloprid in dogs · Medicines most reported with skin rash or irritation