Drooling after Milbemycin Oxime + Spinosad (Trifexis) in dogs

The FDA has received 1,577 reports of drooling in dogs after Milbemycin Oxime + Spinosad. That is 1.2% of all reports for this medicine, compared with 1.4% across reports for all dog medicines.

1,577Reports

31%Marked serious

59%Recovered

5.3%Died or euthanised

Same dayTypical onset

How soon it started

Same day

629 51%

1–2 days

113 9.2%

3–7 days

34 2.8%

1–4 weeks

73 5.9%

Over a month

379 31%

How the animals did

Recovered

789 50%

Recovered with lasting effects

140 8.9%

Still unwell when reported

173 11%

Died

36 2.3%

Euthanised

47 3.0%

Not known

392 25%

Problems reported at the same time

788 50%

631 40%

383 24%

283 18%

279 18%

230 15%

207 13%

165 10%

Age of the animals

Under 1 year

379

1–3 years

609

4–7 years

324

8–11 years

158

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 drooling in dogs?: 1,577 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 the same 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).

Drooling with similar medicines

Drooling after Ivermectin + Pyrantel (Heartgard Plus) 1,096 reports · 0.7% of its reports
Drooling after Moxidectin (ProHeart 6) 730 reports · 1.4% of its reports
Drooling after Milbemycin Oxime + Praziquantel (Interceptor Plus) 420 reports · 1.3% of its reports
Drooling after Milbemycin Oxime (Interceptor) 354 reports · 1.2% of its reports
Drooling after Selamectin (Revolution) 469 reports · 1.6% of its reports
Drooling after Ivermectin (Heartgard) 494 reports · 4.1% of its reports
Drooling after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 166 reports · 1.9% of its reports
Drooling after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 21 reports · 1.8% of its reports

All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with drooling