Heart murmur after Spinosad (Comfortis) in dogs

67 reports to the FDA describe heart murmur in dogs given Spinosad. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

67Reports

82%Marked serious

39%Recovered

27%Died or euthanised

21 daysTypical onset

How soon it started

Same day

9 26%

1–2 days

2 5.7%

3–7 days

0 0.0%

1–4 weeks

7 20%

Over a month

17 49%

How the animals did

Recovered with lasting effects

26 39%

Still unwell when reported

12 18%

Died

10 15%

Euthanised

8 12%

Not known

11 16%

Problems reported at the same time

18 27%

18 27%

15 22%

14 21%

14 21%

12 18%

10 15%

10 15%

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 heart murmur in dogs?: 67 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 21 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).

Heart murmur with similar medicines

Heart murmur after Lufenuron + Milbemycin Oxime (Sentinel) 28 reports · 0.1% of its reports
Heart murmur after Imidacloprid + Moxidectin (Advantage Multi) 30 reports · 0.2% of its reports

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