Drinking a lot after Milbemycin Oxime + Spinosad (Trifexis) in dogs

The FDA has received 229 reports of drinking a lot in dogs after Milbemycin Oxime + Spinosad. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

229Reports

41%Marked serious

51%Recovered

12%Died or euthanised

6 daysTypical onset

How soon it started

Same day

61 38%

1–2 days

15 9.4%

3–7 days

6 3.8%

1–4 weeks

8 5.0%

Over a month

69 43%

How the animals did

Recovered

75 33%

Recovered with lasting effects

42 18%

Still unwell when reported

34 15%

Died

8 3.5%

Euthanised

19 8.3%

Not known

51 22%

Problems reported at the same time

114 50%

107 47%

96 42%

48 21%

41 18%

37 16%

37 16%

27 12%

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 drinking a lot in dogs?: 229 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 6 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).

Drinking a lot with similar medicines

Drinking a lot after Ivermectin + Pyrantel (Heartgard Plus) 118 reports · 0.1% of its reports
Drinking a lot after Moxidectin (ProHeart 6) 37 reports · 0.1% of its reports
Drinking a lot after Milbemycin Oxime + Praziquantel (Interceptor Plus) 83 reports · 0.3% of its reports
Drinking a lot after Ivermectin (Heartgard) 35 reports · 0.3% of its reports

All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with drinking a lot