Allergic reaction after Fipronil in dogs

The FDA has received 22 reports of allergic reaction in dogs after Fipronil. That is 1.6% of all reports for this medicine, compared with 2.3% across reports for all dog medicines.

22Reports

68%Marked serious

36%Recovered

4.5%Died or euthanised

19 daysTypical onset

How soon it started

Same day

3 19%

1–2 days

3 19%

3–7 days

1 6.3%

1–4 weeks

3 19%

Over a month

6 38%

How the animals did

Recovered

6 27%

Recovered with lasting effects

2 9.1%

Still unwell when reported

8 36%

Euthanised

1 4.5%

Not known

5 23%

Problems reported at the same time

7 32%

6 27%

4 18%

4 18%

Licking

4 18%

Lethargy

3 14%

Tremors

3 14%

Diarrhea

3 14%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fipronil kills fleas and ticks (spot-on).

Questions owners ask

Can Fipronil cause allergic reaction in dogs?: 22 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 19 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).

Allergic reaction with similar medicines

Allergic reaction after Spinosad (Comfortis) 534 reports · 0.9% of its reports
Allergic reaction after Lufenuron + Milbemycin Oxime (Sentinel) 337 reports · 1.3% of its reports
Allergic reaction after Imidacloprid + Moxidectin (Advantage Multi) 267 reports · 2.0% of its reports
Allergic reaction after Nitenpyram (Capstar) 189 reports · 1.8% of its reports
Allergic reaction after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 108 reports · 1.1% of its reports
Allergic reaction after Fipronil + S-methoprene (Frontline Plus) 45 reports · 1.5% of its reports
Allergic reaction after Flumethrin + Imidacloprid (Seresto) 31 reports · 1.4% of its reports
Allergic reaction after Imidacloprid 28 reports · 1.5% of its reports
Allergic reaction after Lufenuron 73 reports · 7.2% of its reports

All reported side effects of Fipronil in dogs · Medicines most reported with allergic reaction