Injection site reaction after Milbemycin Oxime + Spinosad (Trifexis) in dogs

39 reports to the FDA describe injection site reaction in dogs given Milbemycin Oxime + Spinosad. That is 0.0% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

39Reports

46%Marked serious

26%Recovered

15%Died or euthanised

65 daysTypical onset

How soon it started

Same day

7 29%

1–2 days

1 4.2%

3–7 days

1 4.2%

1–4 weeks

1 4.2%

Over a month

14 58%

How the animals did

Recovered

10 26%

Still unwell when reported

13 33%

Died

1 2.6%

Euthanised

5 13%

Not known

10 26%

Problems reported at the same time

14 36%

9 23%

8 21%

8 21%

Didn't prevent heartworm

8 21%

Fever

6 15%

Liver problems

6 15%

Death

6 15%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly). Spinosad kills fleas; monthly chewable.

Products with this combination include Trifexis. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Some herding breeds (for example Collies) carry the MDR1 gene variant and can be more sensitive to this drug class at high doses.

Questions owners ask

Can Milbemycin Oxime + Spinosad cause injection site reaction in dogs?: 39 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 65 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).

Injection site reaction with similar medicines

Injection site reaction after Ivermectin + Pyrantel (Heartgard Plus) 301 reports · 0.2% of its reports
Injection site reaction after Moxidectin (ProHeart 6) 1,295 reports · 2.6% of its reports
Injection site reaction after Milbemycin Oxime + Praziquantel (Interceptor Plus) 110 reports · 0.3% of its reports
Injection site reaction after Milbemycin Oxime (Interceptor) 30 reports · 0.1% of its reports
Injection site reaction after Selamectin (Revolution) 29 reports · 0.1% of its reports
Injection site reaction after Ivermectin (Heartgard) 50 reports · 0.4% of its reports

All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with injection site reaction