Lameness after Spinosad (Comfortis) in dogs

122 reports to the FDA describe lameness in dogs given Spinosad. That is 0.2% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported less often than average with this medicine.

122Reports

46%Marked serious

41%Recovered

9.8%Died or euthanised

14 daysTypical onset

How soon it started

Same day

18 31%

1–2 days

6 10%

3–7 days

2 3.4%

1–4 weeks

7 12%

Over a month

26 44%

How the animals did

Recovered

19 16%

Recovered with lasting effects

31 25%

Still unwell when reported

21 17%

Died

8 6.6%

Euthanised

4 3.3%

Not known

39 32%

Problems reported at the same time

37 30%

32 26%

26 21%

22 18%

20 16%

18 15%

16 13%

16 13%

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 lameness in dogs?: 122 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 14 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).

Lameness with similar medicines

Lameness after Lufenuron + Milbemycin Oxime (Sentinel) 62 reports · 0.2% of its reports
Lameness after Imidacloprid + Moxidectin (Advantage Multi) 81 reports · 0.6% of its reports
Lameness after Nitenpyram (Capstar) 35 reports · 0.3% of its reports
Lameness after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 23 reports · 0.2% of its reports
Lameness after Fipronil + S-methoprene (Frontline Plus) 22 reports · 0.7% of its reports
Lameness after Flumethrin + Imidacloprid (Seresto) 41 reports · 1.8% of its reports

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