Didn't stop fleas after Imidacloprid + Pyriproxyfen in dogs

The FDA has received 125 reports of didn't stop fleas in dogs after Imidacloprid + Pyriproxyfen. That is 47% of all reports for this medicine, compared with 6.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

125Reports

15%Marked serious

4.0%Recovered

2.4%Died or euthanised

28 daysTypical onset

How soon it started

Same day

3 3.4%

1–2 days

10 11%

3–7 days

8 9.0%

1–4 weeks

26 29%

Over a month

42 47%

How the animals did

Recovered

5 4.0%

Still unwell when reported

20 16%

Died

3 2.4%

Not known

97 78%

Problems reported at the same time

Itching

48 38%

Seizures

7 5.6%

Hair loss

5 4.0%

Behaviour change

5 4.0%

Didn't work as expected

4 3.2%

Underdose

4 3.2%

Skin rash or irritation

3 2.4%

Restlessness or agitation

3 2.4%

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 didn't stop fleas in dogs?: 125 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 28 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).

Didn't stop fleas with similar medicines

Didn't stop fleas after Spinosad (Comfortis) 13,280 reports · 23% of its reports
Didn't stop fleas after Lufenuron + Milbemycin Oxime (Sentinel) 977 reports · 3.8% of its reports
Didn't stop fleas after Imidacloprid + Moxidectin (Advantage Multi) 1,444 reports · 11% of its reports
Didn't stop fleas after Nitenpyram (Capstar) 6,142 reports · 57% of its reports
Didn't stop fleas after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 498 reports · 5.0% of its reports
Didn't stop fleas after Fipronil + S-methoprene (Frontline Plus) 576 reports · 19% of its reports
Didn't stop fleas after Flumethrin + Imidacloprid (Seresto) 882 reports · 39% of its reports
Didn't stop fleas after Imidacloprid 1,054 reports · 55% of its reports
Didn't stop fleas after Fipronil 394 reports · 28% of its reports
Didn't stop fleas after Lufenuron 44 reports · 4.3% of its reports

All reported side effects of Imidacloprid + Pyriproxyfen in dogs · Medicines most reported with didn't stop fleas