Vomiting after Spinosad (Comfortis) in cats

8,410 reports to the FDA describe vomiting in cats given Spinosad. That is 73% of all reports for this medicine, compared with 18% across reports for all cat medicines, so it is reported unusually often with this medicine.

8,410Reports

3.0%Marked serious

88%Recovered

1.2%Died or euthanised

Same dayTypical onset

How soon it started

Same day

5,786 76%

1–2 days

173 2.3%

3–7 days

55 0.7%

1–4 weeks

282 3.7%

Over a month

1,299 17%

How the animals did

Recovered

7,271 86%

Recovered with lasting effects

134 1.6%

Still unwell when reported

127 1.5%

Died

72 0.9%

Euthanised

28 0.3%

Not known

778 9.3%

Problems reported at the same time

523 6.2%

385 4.6%

321 3.8%

320 3.8%

Didn't work as expected

219 2.6%

Diarrhea

196 2.3%

Accidental exposure

132 1.6%

Behaviour change

123 1.5%

Age of the animals

Under 1 year

663

1–3 years

2,538

4–7 years

1,926

8–11 years

1,408

12+ years

1,175

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 vomiting in cats?: 8,410 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).

Vomiting with similar medicines

Vomiting after Nitenpyram (Capstar) 630 reports · 7.2% of its reports
Vomiting after Imidacloprid + Moxidectin (Advantage Multi) 861 reports · 11% of its reports
Vomiting after Lufenuron 222 reports · 20% of its reports
Vomiting after Flumethrin + Imidacloprid (Seresto) 59 reports · 8.8% of its reports
Vomiting after Imidacloprid + Pyriproxyfen 68 reports · 10% of its reports
Vomiting after Fipronil 82 reports · 16% of its reports
Vomiting after Fipronil + S-methoprene (Frontline Plus) 54 reports · 15% of its reports
Vomiting after Imidacloprid 37 reports · 15% of its reports

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