Leucocytosis after Spinosad (Comfortis) in dogs

228 reports to the FDA describe leucocytosis in dogs given Spinosad. That is 0.4% 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.

228Reports

52%Marked serious

13%Recovered

41%Died or euthanised

8 daysTypical onset

How soon it started

Same day

21 21%

1–2 days

22 22%

3–7 days

6 6.1%

1–4 weeks

10 10%

Over a month

39 40%

How the animals did

Recovered

13 5.7%

Recovered with lasting effects

16 7.0%

Still unwell when reported

25 11%

Died

65 29%

Euthanised

28 12%

Not known

81 36%

Problems reported at the same time

141 62%

125 55%

123 54%

113 50%

93 41%

91 40%

79 35%

77 34%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Spinosad kills fleas; monthly chewable.

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

Questions owners ask

Can Spinosad cause leucocytosis in dogs?: 228 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 8 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 Lufenuron + Milbemycin Oxime (Sentinel) 114 reports · 0.4% of its reports
Leucocytosis after Imidacloprid + Moxidectin (Advantage Multi) 60 reports · 0.5% 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 Spinosad in dogs · Medicines most reported with leucocytosis