Lethargy after Amitraz + Fipronil + S-methoprene in dogs

292 reports to the FDA describe lethargy in dogs given Amitraz + Fipronil + S-methoprene. That is 63% of all reports for this medicine, compared with 11% across reports for all dog medicines, so it is reported unusually often with this medicine.

292Reports

71%Marked serious

54%Recovered

0.7%Died or euthanised

30 daysTypical onset

How soon it started

Same day

50 23%

1–2 days

23 10%

3–7 days

7 3.2%

1–4 weeks

32 14%

Over a month

110 50%

How the animals did

Recovered

158 54%

Still unwell when reported

12 4.1%

Euthanised

2 0.7%

Not known

120 41%

Problems reported at the same time

Vomiting

51 17%

Wobbliness (ataxia)

36 12%

Application site reaction

30 10%

28 9.6%

19 6.5%

17 5.8%

16 5.5%

15 5.1%

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 lethargy in dogs?: 292 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).

Lethargy with similar medicines

Lethargy after Spinosad (Comfortis) 7,303 reports · 13% of its reports
Lethargy after Lufenuron + Milbemycin Oxime (Sentinel) 2,341 reports · 9.0% of its reports
Lethargy after Imidacloprid + Moxidectin (Advantage Multi) 2,000 reports · 15% of its reports
Lethargy after Nitenpyram (Capstar) 1,204 reports · 11% of its reports
Lethargy after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 666 reports · 6.7% of its reports
Lethargy after Fipronil + S-methoprene (Frontline Plus) 447 reports · 15% of its reports
Lethargy after Flumethrin + Imidacloprid (Seresto) 250 reports · 11% of its reports
Lethargy after Imidacloprid 196 reports · 10% of its reports
Lethargy after Fipronil 185 reports · 13% of its reports
Lethargy after Lufenuron 205 reports · 20% of its reports

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