Drug dose omission after Spinosad (Comfortis) in cats

74 reports to the FDA describe drug dose omission in cats given Spinosad. That is 0.6% of all reports for this medicine, compared with 0.1% across reports for all cat medicines, so it is reported unusually often with this medicine.

74Reports

2.7%Marked serious

28%Recovered

1.4%Died or euthanised

104 daysTypical onset

How soon it started

Same day

10 29%

1–2 days

2 5.9%

3–7 days

0 0.0%

1–4 weeks

1 2.9%

Over a month

21 62%

How the animals did

Recovered

21 28%

Still unwell when reported

3 4.1%

Died

1 1.4%

Not known

49 66%

Problems reported at the same time

Didn't stop fleas

50 68%

Vomiting

29 39%

Unpalatable

12 16%

Didn't work as expected

7 9.5%

5 6.8%

4 5.4%

4 5.4%

3 4.1%

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 drug dose omission in cats?: 74 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 104 days 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).

All reported side effects of Spinosad in cats · Medicines most reported with drug dose omission