Tremors after Fipronil + Pyriproxyfen + S-methoprene in dogs

The FDA has received 33 reports of tremors in dogs after Fipronil + Pyriproxyfen + S-methoprene. That is 7.7% of all reports for this medicine, compared with 3.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

33Reports

45%Marked serious

55%Recovered

3.0%Died or euthanised

1 daysTypical onset

How soon it started

Same day

8 35%

1–2 days

5 22%

3–7 days

2 8.7%

1–4 weeks

4 17%

Over a month

4 17%

How the animals did

Recovered

18 55%

Still unwell when reported

2 6.1%

Euthanised

1 3.0%

Not known

12 36%

Problems reported at the same time

Lethargy

11 33%

Seizures

11 33%

Vomiting

6 18%

Wobbliness (ataxia)

6 18%

Weakness

4 12%

Loss of appetite

3 9.1%

Itching

3 9.1%

Breathing problems

3 9.1%

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 Fipronil + Pyriproxyfen + S-methoprene cause tremors in dogs?: 33 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 1 day 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).

Tremors with similar medicines

Tremors after Spinosad (Comfortis) 2,268 reports · 4.0% of its reports
Tremors after Lufenuron + Milbemycin Oxime (Sentinel) 590 reports · 2.3% of its reports
Tremors after Imidacloprid + Moxidectin (Advantage Multi) 837 reports · 6.4% of its reports
Tremors after Nitenpyram (Capstar) 402 reports · 3.7% of its reports
Tremors after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 213 reports · 2.1% of its reports
Tremors after Fipronil + S-methoprene (Frontline Plus) 141 reports · 4.8% of its reports
Tremors after Flumethrin + Imidacloprid (Seresto) 66 reports · 2.9% of its reports
Tremors after Imidacloprid 58 reports · 3.0% of its reports
Tremors after Fipronil 65 reports · 4.6% of its reports
Tremors after Lufenuron 33 reports · 3.2% of its reports

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