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

141 reports to the FDA describe tremors in dogs given Fipronil + S-methoprene. That is 4.8% of all reports for this medicine, compared with 3.4% across reports for all dog medicines.

141Reports

65%Marked serious

48%Recovered

5.7%Died or euthanised

16 daysTypical onset

How soon it started

Same day

17 20%

1–2 days

11 13%

3–7 days

7 8.2%

1–4 weeks

23 27%

Over a month

27 32%

How the animals did

Recovered

67 48%

Recovered with lasting effects

1 0.7%

Still unwell when reported

11 7.8%

Died

4 2.8%

Euthanised

4 2.8%

Not known

54 38%

Problems reported at the same time

33 23%

32 23%

25 18%

22 16%

21 15%

17 12%

14 9.9%

12 8.5%

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 tremors in dogs?: 141 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).

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 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
Tremors after Imidacloprid + Permethrin + Pyriproxyfen 35 reports · 4.7% of its reports

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