Liver problems after Fipronil in dogs

The FDA has received 53 reports of liver problems in dogs after Fipronil. That is 3.8% of all reports for this medicine, compared with 4.6% across reports for all dog medicines.

53Reports

68%Marked serious

23%Recovered

19%Died or euthanised

133 daysTypical onset

How soon it started

Same day

2 5.6%

1–2 days

0 0.0%

3–7 days

1 2.8%

1–4 weeks

10 28%

Over a month

23 64%

How the animals did

Recovered

7 13%

Recovered with lasting effects

5 9.4%

Still unwell when reported

18 34%

Died

5 9.4%

Euthanised

5 9.4%

Not known

13 25%

Problems reported at the same time

20 38%

16 30%

12 23%

11 21%

10 19%

9 17%

Neutrophilia

8 15%

Abnormal radiograph finding

8 15%

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 liver problems in dogs?: 53 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 133 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).

Liver problems with similar medicines

Liver problems after Spinosad (Comfortis) 955 reports · 1.7% of its reports
Liver problems after Lufenuron + Milbemycin Oxime (Sentinel) 414 reports · 1.6% of its reports
Liver problems after Imidacloprid + Moxidectin (Advantage Multi) 197 reports · 1.5% of its reports
Liver problems after Nitenpyram (Capstar) 87 reports · 0.8% of its reports
Liver problems after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 132 reports · 1.3% of its reports
Liver problems after Fipronil + S-methoprene (Frontline Plus) 68 reports · 2.3% of its reports
Liver problems after Flumethrin + Imidacloprid (Seresto) 47 reports · 2.1% of its reports
Liver problems after Lufenuron 53 reports · 5.2% of its reports
Liver problems after Imidacloprid + Permethrin + Pyriproxyfen 21 reports · 2.8% of its reports
Liver problems after Imidacloprid + Permethrin 24 reports · 5.1% of its reports

All reported side effects of Fipronil in dogs · Medicines most reported with liver problems