Anxiety after Fipronil + S-methoprene (Frontline Plus) in dogs

36 reports to the FDA describe anxiety in dogs given Fipronil + S-methoprene. That is 1.2% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported unusually often with this medicine.

36Reports

56%Marked serious

42%Recovered

0.0%Died or euthanised

31 daysTypical onset

How soon it started

Same day

3 21%

1–2 days

0 0.0%

3–7 days

2 14%

1–4 weeks

2 14%

Over a month

7 50%

How the animals did

Recovered

15 42%

Still unwell when reported

3 8.3%

Not known

18 50%

Problems reported at the same time

Behaviour change

14 39%

Breathing problems

10 28%

Restlessness or agitation

9 25%

9 25%

7 19%

6 17%

4 11%

4 11%

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 anxiety in dogs?: 36 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 31 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).

Anxiety with similar medicines

Anxiety after Spinosad (Comfortis) 141 reports · 0.2% of its reports
Anxiety after Lufenuron + Milbemycin Oxime (Sentinel) 113 reports · 0.4% of its reports
Anxiety after Imidacloprid + Moxidectin (Advantage Multi) 103 reports · 0.8% of its reports
Anxiety after Nitenpyram (Capstar) 63 reports · 0.6% of its reports
Anxiety after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 36 reports · 0.4% of its reports
Anxiety after Flumethrin + Imidacloprid (Seresto) 23 reports · 1.0% of its reports
Anxiety after Fipronil 23 reports · 1.6% of its reports
Anxiety after Cyphenothrin + Fipronil + S-methoprene 39 reports · 6.0% of its reports

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