Diarrhea after Spinosad (Comfortis) in cats

277 reports to the FDA describe diarrhea in cats given Spinosad. That is 2.4% of all reports for this medicine, compared with 5.1% across reports for all cat medicines, so it is reported less often than average with this medicine.

277Reports
27%Marked serious
57%Recovered
11%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
158 63%
1–2 days
24 9.6%
3–7 days
10 4.0%
1–4 weeks
25 10.0%
Over a month
34 14%

How the animals did

Recovered
128 46%
Recovered with lasting effects
30 11%
Still unwell when reported
24 8.7%
Died
20 7.2%
Euthanised
11 4.0%
Not known
64 23%

Problems reported at the same time

Age of the animals

Under 1 year
35
1–3 years
77
4–7 years
39
8–11 years
40
12+ years
64

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 diarrhea in cats?
277 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).

Diarrhea with similar medicines

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