Pr-liver, lesion(s) after Spinosad (Comfortis) in dogs

The FDA has received 29 reports of pr-liver, lesion(s) in dogs after Spinosad. That is 0.1% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

29Reports

24%Marked serious

0.0%Recovered

69%Died or euthanised

–Typical onset

How the animals did

Still unwell when reported

1 3.4%

Died

17 59%

Euthanised

3 10%

Not known

8 28%

Problems reported at the same time

19 66%

19 66%

18 62%

15 52%

13 45%

11 38%

Pr-spleen, lesion(s)

8 28%

Swelling

6 21%

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 pr-liver, lesion(s) in dogs?: 29 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.
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).

All reported side effects of Spinosad in dogs · Medicines most reported with pr-liver, lesion(s)