Swelling after Spinosad (Comfortis) in cats

40 reports to the FDA describe swelling in cats given Spinosad. That is 0.3% of all reports for this medicine, compared with 1.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

40Reports

85%Marked serious

20%Recovered

73%Died or euthanised

1 daysTypical onset

How soon it started

Same day

16 46%

1–2 days

8 23%

3–7 days

1 2.9%

1–4 weeks

2 5.7%

Over a month

8 23%

How the animals did

Recovered

7 18%

Recovered with lasting effects

1 2.5%

Still unwell when reported

3 7.5%

Died

25 63%

Euthanised

4 10%

Problems reported at the same time

Death

27 68%

Nt - abnormal necropsy finding

17 43%

Pulmonary congestion

11 28%

10 25%

9 23%

9 23%

7 18%

7 18%

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 swelling in cats?: 40 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).

Swelling with similar medicines

Swelling after Nitenpyram (Capstar) 44 reports · 0.5% of its reports
Swelling after Imidacloprid + Moxidectin (Advantage Multi) 72 reports · 0.9% of its reports
Swelling after Lufenuron 121 reports · 11% of its reports

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