Elevated gamma-glutamyl transferase (ggt) after Milbemycin Oxime + Spinosad (Trifexis) in dogs

129 reports to the FDA describe elevated gamma-glutamyl transferase (ggt) in dogs given Milbemycin Oxime + Spinosad. That is 0.1% of all reports for this medicine, compared with 0.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

129Reports
76%Marked serious
26%Recovered
19%Died or euthanised
24 daysTypical onset
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How soon it started

Same day
13 17%
1–2 days
14 18%
3–7 days
5 6.4%
1–4 weeks
12 15%
Over a month
34 44%

How the animals did

Recovered
16 12%
Recovered with lasting effects
17 13%
Still unwell when reported
33 26%
Died
12 9.3%
Euthanised
12 9.3%
Not known
39 30%

Problems reported at the same time

Liver problems
116 90%
Vomiting
59 46%
Lethargy
58 45%
Loss of appetite
49 38%
Diarrhea
36 28%
Abnormal ultrasound finding
26 20%
Blood problems
25 19%
Kidney problems
25 19%

Age of the animals

Under 1 year
10
1–3 years
22
4–7 years
30
8–11 years
46
12+ years
20

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 elevated gamma-glutamyl transferase (ggt) in dogs?
129 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 24 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).

Elevated gamma-glutamyl transferase (ggt) with similar medicines

All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with elevated gamma-glutamyl transferase (ggt)