Tremors after Spinosad (Comfortis) in dogs

2,268 reports to the FDA describe tremors in dogs given Spinosad. That is 4.0% of all reports for this medicine, compared with 3.4% across reports for all dog medicines.

2,268Reports

20%Marked serious

37%Recovered

4.4%Died or euthanised

1 daysTypical onset

How soon it started

Same day

516 47%

1–2 days

150 14%

3–7 days

37 3.4%

1–4 weeks

62 5.7%

Over a month

324 30%

How the animals did

Recovered

634 28%

Recovered with lasting effects

202 8.9%

Still unwell when reported

116 5.1%

Died

69 3.0%

Euthanised

31 1.4%

Not known

1,216 54%

Problems reported at the same time

950 42%

746 33%

443 20%

376 17%

245 11%

222 9.8%

217 9.6%

166 7.3%

Age of the animals

Under 1 year

339

1–3 years

830

4–7 years

526

8–11 years

328

12+ years

160

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 tremors in dogs?: 2,268 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).

Tremors with similar medicines

Tremors after Lufenuron + Milbemycin Oxime (Sentinel) 590 reports · 2.3% of its reports
Tremors after Imidacloprid + Moxidectin (Advantage Multi) 837 reports · 6.4% of its reports
Tremors after Nitenpyram (Capstar) 402 reports · 3.7% of its reports
Tremors after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 213 reports · 2.1% of its reports
Tremors after Fipronil + S-methoprene (Frontline Plus) 141 reports · 4.8% of its reports
Tremors after Flumethrin + Imidacloprid (Seresto) 66 reports · 2.9% of its reports
Tremors after Imidacloprid 58 reports · 3.0% of its reports
Tremors after Fipronil 65 reports · 4.6% of its reports
Tremors after Lufenuron 33 reports · 3.2% of its reports
Tremors after Imidacloprid + Permethrin + Pyriproxyfen 35 reports · 4.7% of its reports

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