Anxiety after Milbemycin Oxime + Spinosad (Trifexis) in dogs

623 reports to the FDA describe anxiety in dogs given Milbemycin Oxime + Spinosad. That is 0.5% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

623Reports

30%Marked serious

48%Recovered

4.2%Died or euthanised

1 daysTypical onset

How soon it started

Same day

195 47%

1–2 days

32 7.8%

3–7 days

7 1.7%

1–4 weeks

20 4.9%

Over a month

157 38%

How the animals did

Recovered

232 37%

Recovered with lasting effects

70 11%

Still unwell when reported

127 20%

Died

11 1.8%

Euthanised

15 2.4%

Not known

168 27%

Problems reported at the same time

213 34%

154 25%

144 23%

139 22%

136 22%

102 16%

Restlessness or agitation

93 15%

Diarrhea

74 12%

Age of the animals

Under 1 year

1–3 years

229

4–7 years

170

8–11 years

121

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 anxiety in dogs?: 623 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).

Anxiety with similar medicines

Anxiety after Ivermectin + Pyrantel (Heartgard Plus) 382 reports · 0.3% of its reports
Anxiety after Moxidectin (ProHeart 6) 156 reports · 0.3% of its reports
Anxiety after Milbemycin Oxime + Praziquantel (Interceptor Plus) 194 reports · 0.6% of its reports
Anxiety after Milbemycin Oxime (Interceptor) 70 reports · 0.2% of its reports
Anxiety after Selamectin (Revolution) 54 reports · 0.2% of its reports
Anxiety after Ivermectin (Heartgard) 75 reports · 0.6% of its reports
Anxiety after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 30 reports · 0.4% of its reports

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