Didn't work as expected after Imidacloprid in dogs

The FDA has received 105 reports of didn't work as expected in dogs after Imidacloprid. That is 5.5% of all reports for this medicine, compared with 13% across reports for all dog medicines, so it is reported less often than average with this medicine.

105Reports

2.9%Marked serious

6.7%Recovered

1.0%Died or euthanised

7 daysTypical onset

How soon it started

Same day

20 23%

1–2 days

21 24%

3–7 days

12 14%

1–4 weeks

22 25%

Over a month

12 14%

How the animals did

Recovered

7 6.7%

Still unwell when reported

3 2.9%

Euthanised

1 1.0%

Not known

94 90%

Problems reported at the same time

21 20%

13 12%

7 6.7%

5 4.8%

5 4.8%

4 3.8%

Loose stool

3 2.9%

Didn't stop ticks

3 2.9%

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 cause didn't work as expected in dogs?: 105 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 7 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 work as expected with similar medicines

Didn't work as expected after Spinosad (Comfortis) 1,731 reports · 3.0% of its reports
Didn't work as expected after Lufenuron + Milbemycin Oxime (Sentinel) 4,480 reports · 17% of its reports
Didn't work as expected after Imidacloprid + Moxidectin (Advantage Multi) 631 reports · 4.8% of its reports
Didn't work as expected after Nitenpyram (Capstar) 803 reports · 7.4% of its reports
Didn't work as expected after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 1,429 reports · 14% of its reports
Didn't work as expected after Fipronil + S-methoprene (Frontline Plus) 243 reports · 8.2% of its reports
Didn't work as expected after Flumethrin + Imidacloprid (Seresto) 209 reports · 9.2% of its reports
Didn't work as expected after Fipronil 152 reports · 11% of its reports
Didn't work as expected after Imidacloprid + Permethrin + Pyriproxyfen 30 reports · 4.1% of its reports
Didn't work as expected after Imidacloprid + Permethrin 70 reports · 15% of its reports

All reported side effects of Imidacloprid in dogs · Medicines most reported with didn't work as expected