Eye disorder (for photophobia see 'neurological') after Milbemycin Oxime + Spinosad (Trifexis) in dogs

The FDA has received 596 reports of eye disorder (for photophobia see 'neurological') in dogs after Milbemycin Oxime + Spinosad. That is 0.5% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

596Reports

40%Marked serious

57%Recovered

5.5%Died or euthanised

1 daysTypical onset

How soon it started

Same day

224 49%

1–2 days

32 6.9%

3–7 days

8 1.7%

1–4 weeks

33 7.2%

Over a month

164 36%

How the animals did

Recovered

243 41%

Recovered with lasting effects

98 16%

Still unwell when reported

77 13%

Died

15 2.5%

Euthanised

18 3.0%

Not known

145 24%

Problems reported at the same time

297 50%

179 30%

139 23%

127 21%

109 18%

57 9.6%

56 9.4%

54 9.1%

Age of the animals

Under 1 year

106

1–3 years

209

4–7 years

142

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 eye disorder (for photophobia see 'neurological') in dogs?: 596 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).

Eye disorder (for photophobia see 'neurological') with similar medicines

Eye disorder (for photophobia see 'neurological') after Ivermectin + Pyrantel (Heartgard Plus) 126 reports · 0.1% of its reports
Eye disorder (for photophobia see 'neurological') after Moxidectin (ProHeart 6) 70 reports · 0.1% of its reports
Eye disorder (for photophobia see 'neurological') after Milbemycin Oxime + Praziquantel (Interceptor Plus) 60 reports · 0.2% of its reports
Eye disorder (for photophobia see 'neurological') after Milbemycin Oxime (Interceptor) 33 reports · 0.1% of its reports
Eye disorder (for photophobia see 'neurological') after Selamectin (Revolution) 49 reports · 0.2% of its reports
Eye disorder (for photophobia see 'neurological') after Ivermectin (Heartgard) 65 reports · 0.5% of its reports

All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with eye disorder (for photophobia see 'neurological')