Allergic reaction after Spinosad (Comfortis) in dogs

The FDA has received 534 reports of allergic reaction in dogs after Spinosad. That is 0.9% of all reports for this medicine, compared with 2.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

534Reports

19%Marked serious

32%Recovered

2.1%Died or euthanised

2 daysTypical onset

How soon it started

Same day

87 42%

1–2 days

24 12%

3–7 days

10 4.8%

1–4 weeks

25 12%

Over a month

62 30%

How the animals did

Recovered

133 25%

Recovered with lasting effects

37 6.9%

Still unwell when reported

37 6.9%

Died

6 1.1%

Euthanised

5 0.9%

Not known

316 59%

Problems reported at the same time

154 29%

119 22%

108 20%

78 15%

44 8.2%

Skin rash or irritation

40 7.5%

Didn't stop fleas

33 6.2%

Loss of appetite

26 4.9%

Age of the animals

Under 1 year

1–3 years

209

4–7 years

145

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 allergic reaction in dogs?: 534 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 2 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).

Allergic reaction with similar medicines

Allergic reaction after Lufenuron + Milbemycin Oxime (Sentinel) 337 reports · 1.3% of its reports
Allergic reaction after Imidacloprid + Moxidectin (Advantage Multi) 267 reports · 2.0% of its reports
Allergic reaction after Nitenpyram (Capstar) 189 reports · 1.8% of its reports
Allergic reaction after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 108 reports · 1.1% of its reports
Allergic reaction after Fipronil + S-methoprene (Frontline Plus) 45 reports · 1.5% of its reports
Allergic reaction after Flumethrin + Imidacloprid (Seresto) 31 reports · 1.4% of its reports
Allergic reaction after Imidacloprid 28 reports · 1.5% of its reports
Allergic reaction after Fipronil 22 reports · 1.6% of its reports
Allergic reaction after Lufenuron 73 reports · 7.2% of its reports

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