Death after Spinosad (Comfortis) in cats

The FDA has received 322 reports of death in cats after Spinosad. That is 2.8% of all reports for this medicine, compared with 8.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

322Reports
95%Marked serious
0.3%Recovered
99%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
103 40%
1–2 days
52 20%
3–7 days
18 7.0%
1–4 weeks
23 8.9%
Over a month
61 24%

How the animals did

Recovered with lasting effects
1 0.3%
Still unwell when reported
1 0.3%
Died
258 80%
Euthanised
61 19%
Not known
1 0.3%

Problems reported at the same time

Age of the animals

Under 1 year
20
1–3 years
57
4–7 years
60
8–11 years
69
12+ years
81

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 death in cats?
322 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).

Death with similar medicines

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