Itching after Cyphenothrin + Fipronil + S-methoprene in dogs

301 reports to the FDA describe itching in dogs given Cyphenothrin + Fipronil + S-methoprene. That is 46% of all reports for this medicine, compared with 4.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

301Reports

84%Marked serious

41%Recovered

0.0%Died or euthanised

1 daysTypical onset

How soon it started

Same day

86 43%

1–2 days

19 9.5%

3–7 days

14 7.0%

1–4 weeks

17 8.5%

Over a month

65 32%

How the animals did

Recovered

123 41%

Still unwell when reported

11 3.7%

Not known

167 55%

Problems reported at the same time

Restlessness or agitation

109 36%

Application site reaction

48 16%

32 11%

31 10%

29 9.6%

19 6.3%

Skin rash or irritation

18 6.0%

Hair loss

17 5.6%

Age of the animals

Under 1 year

1–3 years

4–7 years

108

8–11 years

12+ years

About this medicine

Fipronil kills fleas and ticks (spot-on).

Questions owners ask

Can Cyphenothrin + Fipronil + S-methoprene cause itching in dogs?: 301 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).

Itching with similar medicines

Itching after Spinosad (Comfortis) 3,874 reports · 6.8% of its reports
Itching after Lufenuron + Milbemycin Oxime (Sentinel) 1,223 reports · 4.7% of its reports
Itching after Imidacloprid + Moxidectin (Advantage Multi) 2,227 reports · 17% of its reports
Itching after Nitenpyram (Capstar) 1,450 reports · 13% of its reports
Itching after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 281 reports · 2.8% of its reports
Itching after Fipronil + S-methoprene (Frontline Plus) 330 reports · 11% of its reports
Itching after Flumethrin + Imidacloprid (Seresto) 610 reports · 27% of its reports
Itching after Imidacloprid 297 reports · 16% of its reports
Itching after Fipronil 138 reports · 9.8% of its reports
Itching after Lufenuron 178 reports · 17% of its reports

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