Frequent urination after Milbemycin Oxime + Spinosad (Trifexis) in dogs

113 reports to the FDA describe frequent urination 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, so it is reported less often than average with this medicine.

113Reports
43%Marked serious
46%Recovered
7.1%Died or euthanised
1 daysTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
34 38%
1–2 days
16 18%
3–7 days
5 5.6%
1–4 weeks
5 5.6%
Over a month
29 33%

How the animals did

Recovered
30 27%
Recovered with lasting effects
22 19%
Still unwell when reported
26 23%
Died
2 1.8%
Euthanised
6 5.3%
Not known
27 24%

Problems reported at the same time

Age of the animals

Under 1 year
28
1–3 years
29
4–7 years
21
8–11 years
21
12+ years
8

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 frequent urination in dogs?
113 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).

Frequent urination with similar medicines

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