Underdose after Imidacloprid in dogs

The FDA has received 48 reports of underdose in dogs after Imidacloprid. That is 2.5% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported unusually often with this medicine.

48Reports

10%Marked serious

4.2%Recovered

2.1%Died or euthanised

1 daysTypical onset

How soon it started

Same day

11 26%

1–2 days

23 53%

3–7 days

4 9.3%

1–4 weeks

4 9.3%

Over a month

1 2.3%

How the animals did

Recovered

2 4.2%

Still unwell when reported

2 4.2%

Died

1 2.1%

Not known

43 90%

Problems reported at the same time

26 54%

7 15%

7 15%

5 10%

4 8.3%

3 6.3%

3 6.3%

Drug administration error

3 6.3%

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 underdose in dogs?: 48 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).

Underdose with similar medicines

Underdose after Spinosad (Comfortis) 365 reports · 0.6% of its reports
Underdose after Lufenuron + Milbemycin Oxime (Sentinel) 332 reports · 1.3% of its reports
Underdose after Imidacloprid + Moxidectin (Advantage Multi) 144 reports · 1.1% of its reports
Underdose after Nitenpyram (Capstar) 139 reports · 1.3% of its reports
Underdose after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 132 reports · 1.3% of its reports
Underdose after Fipronil + S-methoprene (Frontline Plus) 31 reports · 1.0% of its reports

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