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

79 reports to the FDA describe wobbliness (ataxia) in dogs given Fipronil + S-methoprene. That is 2.7% of all reports for this medicine, compared with 2.6% across reports for all dog medicines.

79Reports

68%Marked serious

43%Recovered

8.9%Died or euthanised

8 daysTypical onset

How soon it started

Same day

10 24%

1–2 days

7 17%

3–7 days

3 7.3%

1–4 weeks

6 15%

Over a month

15 37%

How the animals did

Recovered

33 42%

Recovered with lasting effects

1 1.3%

Still unwell when reported

9 11%

Died

2 2.5%

Euthanised

5 6.3%

Not known

29 37%

Problems reported at the same time

26 33%

22 28%

17 22%

17 22%

14 18%

12 15%

10 13%

9 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 wobbliness (ataxia) in dogs?: 79 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 8 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).

Wobbliness (ataxia) with similar medicines

Wobbliness (ataxia) after Spinosad (Comfortis) 1,456 reports · 2.6% of its reports
Wobbliness (ataxia) after Lufenuron + Milbemycin Oxime (Sentinel) 504 reports · 1.9% of its reports
Wobbliness (ataxia) after Imidacloprid + Moxidectin (Advantage Multi) 658 reports · 5.0% of its reports
Wobbliness (ataxia) after Nitenpyram (Capstar) 219 reports · 2.0% of its reports
Wobbliness (ataxia) after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 167 reports · 1.7% of its reports
Wobbliness (ataxia) after Flumethrin + Imidacloprid (Seresto) 45 reports · 2.0% of its reports
Wobbliness (ataxia) after Imidacloprid 61 reports · 3.2% of its reports
Wobbliness (ataxia) after Fipronil 32 reports · 2.3% of its reports
Wobbliness (ataxia) after Lufenuron 27 reports · 2.7% of its reports
Wobbliness (ataxia) after Imidacloprid + Permethrin + Pyriproxyfen 29 reports · 3.9% of its reports

All reported side effects of Fipronil + S-methoprene in dogs · Medicines most reported with wobbliness (ataxia)