Restlessness or agitation after Fipronil in cats

The FDA has received 59 reports of restlessness or agitation in cats after Fipronil. That is 12% of all reports for this medicine, compared with 4.9% across reports for all cat medicines, so it is reported unusually often with this medicine.

59Reports

17%Marked serious

68%Recovered

0.0%Died or euthanised

10 daysTypical onset

How soon it started

Same day

13 30%

1–2 days

4 9.3%

3–7 days

4 9.3%

1–4 weeks

17 40%

Over a month

5 12%

How the animals did

Recovered

40 68%

Still unwell when reported

7 12%

Not known

12 20%

Problems reported at the same time

Breathing problems

32 54%

Itching

21 36%

Vocalising

14 24%

Increased heart rate

6 10%

Lethargy

6 10%

Licking

6 10%

Anxiety

5 8.5%

Excessive licking and/or grooming

4 6.8%

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 restlessness or agitation in cats?: 59 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 10 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).

Restlessness or agitation with similar medicines

Restlessness or agitation after Spinosad (Comfortis) 229 reports · 2.0% of its reports
Restlessness or agitation after Nitenpyram (Capstar) 2,987 reports · 34% of its reports
Restlessness or agitation after Imidacloprid + Moxidectin (Advantage Multi) 682 reports · 8.4% of its reports
Restlessness or agitation after Lufenuron 20 reports · 1.8% of its reports
Restlessness or agitation after Flumethrin + Imidacloprid (Seresto) 27 reports · 4.0% of its reports
Restlessness or agitation after Imidacloprid + Pyriproxyfen 46 reports · 7.0% of its reports
Restlessness or agitation after Fipronil + S-methoprene (Frontline Plus) 33 reports · 9.0% of its reports
Restlessness or agitation after Imidacloprid 28 reports · 11% of its reports

All reported side effects of Fipronil in cats · Medicines most reported with restlessness or agitation