Leucocytosis after Imidacloprid + Moxidectin (Advantage Multi) in dogs

The FDA has received 60 reports of leucocytosis in dogs after Imidacloprid + Moxidectin. That is 0.5% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

60Reports

78%Marked serious

20%Recovered

25%Died or euthanised

4 daysTypical onset

How soon it started

Same day

8 19%

1–2 days

11 26%

3–7 days

8 19%

1–4 weeks

7 16%

Over a month

9 21%

How the animals did

Recovered

11 18%

Recovered with lasting effects

1 1.7%

Still unwell when reported

6 10%

Died

8 13%

Euthanised

7 12%

Not known

27 45%

Problems reported at the same time

31 52%

31 52%

27 45%

23 38%

20 33%

20 33%

17 28%

14 23%

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). Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs).

Products with this combination include Advantage Multi. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Imidacloprid + Moxidectin cause leucocytosis in dogs?: 60 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 4 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).

Leucocytosis with similar medicines

Leucocytosis after Spinosad (Comfortis) 228 reports · 0.4% of its reports
Leucocytosis after Lufenuron + Milbemycin Oxime (Sentinel) 114 reports · 0.4% of its reports
Leucocytosis after Nitenpyram (Capstar) 42 reports · 0.4% of its reports
Leucocytosis after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 34 reports · 0.3% of its reports
Leucocytosis after Flumethrin + Imidacloprid (Seresto) 22 reports · 1.0% of its reports
Leucocytosis after Fipronil 20 reports · 1.4% of its reports
Leucocytosis after Lufenuron 23 reports · 2.3% of its reports

All reported side effects of Imidacloprid + Moxidectin in dogs · Medicines most reported with leucocytosis