Didn't stop ticks after Flumethrin + Imidacloprid (Seresto) in dogs

The FDA has received 158 reports of didn't stop ticks in dogs after Flumethrin + Imidacloprid. That is 7.0% of all reports for this medicine, compared with 2.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

158Reports

11%Marked serious

2.5%Recovered

1.3%Died or euthanised

50 daysTypical onset

How soon it started

Same day

10 9.4%

1–2 days

5 4.7%

3–7 days

5 4.7%

1–4 weeks

23 22%

Over a month

63 59%

How the animals did

Recovered

4 2.5%

Still unwell when reported

40 25%

Euthanised

2 1.3%

Not known

112 71%

Problems reported at the same time

Didn't work as expected

42 27%

15 9.5%

12 7.6%

11 7.0%

8 5.1%

8 5.1%

7 4.4%

5 3.2%

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 didn't stop ticks in dogs?: 158 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 50 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).

Didn't stop ticks with similar medicines

Didn't stop ticks after Spinosad (Comfortis) 95 reports · 0.2% of its reports
Didn't stop ticks after Lufenuron + Milbemycin Oxime (Sentinel) 42 reports · 0.2% of its reports
Didn't stop ticks after Imidacloprid + Moxidectin (Advantage Multi) 52 reports · 0.4% of its reports
Didn't stop ticks after Nitenpyram (Capstar) 51 reports · 0.5% of its reports
Didn't stop ticks after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 36 reports · 0.4% of its reports
Didn't stop ticks after Fipronil + S-methoprene (Frontline Plus) 117 reports · 4.0% of its reports
Didn't stop ticks after Imidacloprid + Permethrin + Pyriproxyfen 21 reports · 2.8% of its reports
Didn't stop ticks after Fipronil + Pyriproxyfen + S-methoprene 33 reports · 7.7% of its reports

All reported side effects of Flumethrin + Imidacloprid in dogs · Medicines most reported with didn't stop ticks