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

The FDA has received 627 reports of vomiting in dogs after Fipronil + S-methoprene. That is 21% of all reports for this medicine, compared with 28% across reports for all dog medicines.

627Reports

56%Marked serious

58%Recovered

3.3%Died or euthanised

26 daysTypical onset

How soon it started

Same day

75 21%

1–2 days

32 8.8%

3–7 days

22 6.0%

1–4 weeks

62 17%

Over a month

174 48%

How the animals did

Recovered

358 57%

Recovered with lasting effects

8 1.3%

Still unwell when reported

34 5.4%

Died

8 1.3%

Euthanised

13 2.1%

Not known

206 33%

Problems reported at the same time

158 25%

109 17%

105 17%

32 5.1%

31 4.9%

30 4.8%

28 4.5%

27 4.3%

Age of the animals

Under 1 year

102

1–3 years

160

4–7 years

168

8–11 years

119

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 vomiting in dogs?: 627 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 26 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).

Vomiting with similar medicines

Vomiting after Spinosad (Comfortis) 30,909 reports · 54% of its reports
Vomiting after Lufenuron + Milbemycin Oxime (Sentinel) 4,725 reports · 18% of its reports
Vomiting after Imidacloprid + Moxidectin (Advantage Multi) 1,904 reports · 15% of its reports
Vomiting after Nitenpyram (Capstar) 1,204 reports · 11% of its reports
Vomiting after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 1,925 reports · 19% of its reports
Vomiting after Flumethrin + Imidacloprid (Seresto) 295 reports · 13% of its reports
Vomiting after Imidacloprid 251 reports · 13% of its reports
Vomiting after Fipronil 417 reports · 30% of its reports
Vomiting after Lufenuron 325 reports · 32% of its reports
Vomiting after Imidacloprid + Permethrin + Pyriproxyfen 116 reports · 16% of its reports

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