Loose stool after Spinosad (Comfortis) in dogs

236 reports to the FDA describe loose stool in dogs given Spinosad. That is 0.4% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported less often than average with this medicine.

236Reports
21%Marked serious
43%Recovered
4.2%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
51 40%
1–2 days
21 16%
3–7 days
9 7.0%
1–4 weeks
7 5.5%
Over a month
40 31%

How the animals did

Recovered
77 33%
Recovered with lasting effects
25 11%
Still unwell when reported
17 7.2%
Died
7 3.0%
Euthanised
3 1.3%
Not known
107 45%

Problems reported at the same time

Age of the animals

Under 1 year
25
1–3 years
80
4–7 years
53
8–11 years
46
12+ years
24

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 loose stool in dogs?
236 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).

Loose stool with similar medicines

All reported side effects of Spinosad in dogs · Medicines most reported with loose stool