Behaviour change after Imidacloprid in dogs

The FDA has received 94 reports of behaviour change in dogs after Imidacloprid. That is 4.9% of all reports for this medicine, compared with 2.5% across reports for all dog medicines, so it is reported unusually often with this medicine.

94Reports

19%Marked serious

22%Recovered

2.1%Died or euthanised

Same dayTypical onset

How soon it started

Same day

47 55%

1–2 days

24 28%

3–7 days

4 4.7%

1–4 weeks

5 5.9%

Over a month

5 5.9%

How the animals did

Recovered

21 22%

Still unwell when reported

24 26%

Died

1 1.1%

Euthanised

1 1.1%

Not known

47 50%

Problems reported at the same time

27 29%

20 21%

17 18%

14 15%

12 13%

Restlessness or agitation

11 12%

Tremors

11 12%

Overdose

11 12%

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 behaviour change in dogs?: 94 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 the same 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).

Behaviour change with similar medicines

Behaviour change after Spinosad (Comfortis) 1,176 reports · 2.1% of its reports
Behaviour change after Lufenuron + Milbemycin Oxime (Sentinel) 358 reports · 1.4% of its reports
Behaviour change after Imidacloprid + Moxidectin (Advantage Multi) 1,205 reports · 9.2% of its reports
Behaviour change after Nitenpyram (Capstar) 323 reports · 3.0% of its reports
Behaviour change after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 128 reports · 1.3% of its reports
Behaviour change after Fipronil + S-methoprene (Frontline Plus) 181 reports · 6.1% of its reports
Behaviour change after Flumethrin + Imidacloprid (Seresto) 167 reports · 7.3% of its reports
Behaviour change after Fipronil 66 reports · 4.7% of its reports
Behaviour change after Lufenuron 20 reports · 2.0% of its reports
Behaviour change after Imidacloprid + Permethrin + Pyriproxyfen 70 reports · 9.5% of its reports

All reported side effects of Imidacloprid in dogs · Medicines most reported with behaviour change