Distension of abdomen after Milbemycin Oxime + Spinosad (Trifexis) in dogs

164 reports to the FDA describe distension of abdomen in dogs given Milbemycin Oxime + Spinosad. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

164Reports
70%Marked serious
36%Recovered
30%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
43 35%
1–2 days
17 14%
3–7 days
7 5.7%
1–4 weeks
13 11%
Over a month
43 35%

How the animals did

Recovered
37 23%
Recovered with lasting effects
22 13%
Still unwell when reported
24 15%
Died
21 13%
Euthanised
28 17%
Not known
32 20%

Problems reported at the same time

Age of the animals

Under 1 year
22
1–3 years
23
4–7 years
41
8–11 years
58
12+ years
19

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 distension of abdomen in dogs?
164 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 3 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).

Distension of abdomen with similar medicines

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