Seizures after Spinosad (Comfortis) in cats

The FDA has received 101 reports of seizures in cats after Spinosad. That is 0.9% of all reports for this medicine, compared with 2.6% across reports for all cat medicines, so it is reported less often than average with this medicine.

101Reports

85%Marked serious

36%Recovered

42%Died or euthanised

Same dayTypical onset

How soon it started

Same day

49 55%

1–2 days

8 9.0%

3–7 days

6 6.7%

1–4 weeks

7 7.9%

Over a month

19 21%

How the animals did

Recovered

33 33%

Recovered with lasting effects

3 3.0%

Still unwell when reported

7 6.9%

Died

34 34%

Euthanised

8 7.9%

Not known

16 16%

Problems reported at the same time

41 41%

39 39%

30 30%

16 16%

14 14%

14 14%

13 13%

12 12%

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 seizures in cats?: 101 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).

Seizures with similar medicines

Seizures after Nitenpyram (Capstar) 187 reports · 2.1% of its reports
Seizures after Imidacloprid + Moxidectin (Advantage Multi) 156 reports · 1.9% of its reports

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