Overdose after Spinosad (Comfortis) in cats

125 reports to the FDA describe overdose in cats given Spinosad. That is 1.1% of all reports for this medicine, compared with 0.9% across reports for all cat medicines.

125Reports

12%Marked serious

60%Recovered

2.4%Died or euthanised

Same dayTypical onset

How soon it started

Same day

72 62%

1–2 days

7 6.0%

3–7 days

6 5.2%

1–4 weeks

9 7.8%

Over a month

22 19%

How the animals did

Recovered

70 56%

Recovered with lasting effects

5 4.0%

Still unwell when reported

11 8.8%

Died

2 1.6%

Euthanised

1 0.8%

Not known

36 29%

Problems reported at the same time

81 65%

25 20%

24 19%

15 12%

14 11%

Didn't work as expected

13 10%

Itching

12 9.6%

Loss of appetite

11 8.8%

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 overdose in cats?: 125 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).

Overdose with similar medicines

Overdose after Nitenpyram (Capstar) 91 reports · 1.0% of its reports
Overdose after Imidacloprid + Moxidectin (Advantage Multi) 164 reports · 2.0% of its reports

All reported side effects of Spinosad in cats · Medicines most reported with overdose