Dry skin after Milbemycin Oxime + Spinosad (Trifexis) in dogs

115 reports to the FDA describe dry skin in dogs given Milbemycin Oxime + Spinosad. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

115Reports
13%Marked serious
47%Recovered
0.9%Died or euthanised
13 daysTypical onset
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How soon it started

Same day
32 37%
1–2 days
5 5.8%
3–7 days
5 5.8%
1–4 weeks
17 20%
Over a month
27 31%

How the animals did

Recovered
15 13%
Recovered with lasting effects
39 34%
Still unwell when reported
31 27%
Died
1 0.9%
Not known
29 25%

Problems reported at the same time

Age of the animals

Under 1 year
11
1–3 years
37
4–7 years
39
8–11 years
17
12+ years
7

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 dry skin in dogs?
115 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 13 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).

Dry skin with similar medicines

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