Slow heart rate after Milbemycin Oxime + Spinosad (Trifexis) in dogs
26 reports to the FDA describe slow heart rate in dogs given Milbemycin Oxime + Spinosad. That is 0.0% of all reports for this medicine, compared with 0.0% across reports for all dog medicines.
26Reports
77%Marked serious
38%Recovered
12%Died or euthanised
33 daysTypical onset
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How soon it started
How the animals did
Problems reported at the same time
Age of the animals
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 slow heart rate in dogs?
- 26 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 33 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).
All reported side effects of Milbemycin Oxime + Spinosad in dogs · Medicines most reported with slow heart rate