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

The FDA has received 48 reports of wobbliness (ataxia) in dogs after Amitraz + Fipronil + S-methoprene. That is 10% of all reports for this medicine, compared with 2.6% across reports for all dog medicines, so it is reported unusually often with this medicine.

48Reports

83%Marked serious

42%Recovered

0.0%Died or euthanised

16 daysTypical onset

How soon it started

Same day

12 31%

1–2 days

6 15%

3–7 days

0 0.0%

1–4 weeks

6 15%

Over a month

15 38%

How the animals did

Recovered

19 40%

Recovered with lasting effects

1 2.1%

Still unwell when reported

3 6.3%

Not known

25 52%

Problems reported at the same time

Lethargy

36 75%

Vomiting

7 15%

Bradycardia

6 13%

Inappropriate urination

4 8.3%

Diarrhea

3 6.3%

Loss of appetite

3 6.3%

Seizures

3 6.3%

Drooling

3 6.3%

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 Amitraz + Fipronil + S-methoprene cause wobbliness (ataxia) in dogs?: 48 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 16 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 Fipronil + S-methoprene (Frontline Plus) 79 reports · 2.7% 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

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