Restlessness or agitation after Fipronil + S-methoprene (Frontline Plus) in dogs

The FDA has received 119 reports of restlessness or agitation in dogs after Fipronil + S-methoprene. That is 4.0% of all reports for this medicine, compared with 1.6% across reports for all dog medicines, so it is reported unusually often with this medicine.

119Reports

64%Marked serious

57%Recovered

2.5%Died or euthanised

30 daysTypical onset

How soon it started

Same day

16 26%

1–2 days

5 8.2%

3–7 days

4 6.6%

1–4 weeks

6 9.8%

Over a month

30 49%

How the animals did

Recovered

68 57%

Still unwell when reported

10 8.4%

Died

3 2.5%

Not known

38 32%

Problems reported at the same time

34 29%

28 24%

25 21%

18 15%

13 11%

10 8.4%

10 8.4%

Application site reaction

9 7.6%

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).

Products with this combination include Frontline Plus. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Fipronil + S-methoprene cause restlessness or agitation in dogs?: 119 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 30 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) 658 reports · 1.2% of its reports
Restlessness or agitation after Lufenuron + Milbemycin Oxime (Sentinel) 255 reports · 1.0% of its reports
Restlessness or agitation after Imidacloprid + Moxidectin (Advantage Multi) 835 reports · 6.4% of its reports
Restlessness or agitation after Nitenpyram (Capstar) 596 reports · 5.5% of its reports
Restlessness or agitation after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 73 reports · 0.7% of its reports
Restlessness or agitation after Flumethrin + Imidacloprid (Seresto) 68 reports · 3.0% of its reports
Restlessness or agitation after Imidacloprid 44 reports · 2.3% of its reports
Restlessness or agitation after Fipronil 40 reports · 2.8% of its reports
Restlessness or agitation after Imidacloprid + Permethrin + Pyriproxyfen 56 reports · 7.6% of its reports
Restlessness or agitation after Cyphenothrin + Fipronil + S-methoprene 222 reports · 34% of its reports

All reported side effects of Fipronil + S-methoprene in dogs · Medicines most reported with restlessness or agitation