Itching after Imidacloprid + Pyriproxyfen in dogs

The FDA has received 91 reports of itching in dogs after Imidacloprid + Pyriproxyfen. That is 34% 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.

91Reports

31%Marked serious

20%Recovered

0.0%Died or euthanised

26 daysTypical onset

How soon it started

Same day

4 6.3%

1–2 days

3 4.7%

3–7 days

9 14%

1–4 weeks

23 36%

Over a month

25 39%

How the animals did

Recovered

18 20%

Still unwell when reported

18 20%

Not known

55 60%

Problems reported at the same time

Didn't stop fleas

48 53%

Skin rash or irritation

12 13%

Breathing problems

12 13%

Skin redness

11 12%

Behaviour change

9 9.9%

Restlessness or agitation

8 8.8%

Hair loss

6 6.6%

Skin sore

6 6.6%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Imidacloprid kills fleas (spot-on or collar).

Questions owners ask

Can Imidacloprid + Pyriproxyfen cause itching in dogs?: 91 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).

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 Imidacloprid + Pyriproxyfen in dogs · Medicines most reported with itching