Fever after Spinosad (Comfortis) in dogs

The FDA has received 412 reports of fever in dogs after Spinosad. That is 0.7% of all reports for this medicine, compared with 1.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

412Reports
28%Marked serious
24%Recovered
13%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
67 42%
1–2 days
35 22%
3–7 days
8 5.0%
1–4 weeks
8 5.0%
Over a month
43 27%

How the animals did

Recovered
70 17%
Recovered with lasting effects
29 7.0%
Still unwell when reported
28 6.8%
Died
35 8.5%
Euthanised
18 4.4%
Not known
232 56%

Problems reported at the same time

Age of the animals

Under 1 year
72
1–3 years
135
4–7 years
109
8–11 years
64
12+ years
21

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 fever in dogs?
412 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).

Fever with similar medicines

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