Heart failure after Moxidectin (ProHeart 6) in dogs

The FDA has received 45 reports of heart failure in dogs after Moxidectin. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

45Reports
40%Marked serious
0.0%Recovered
76%Died or euthanised
7 daysTypical onset
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How soon it started

Same day
3 19%
1–2 days
3 19%
3–7 days
3 19%
1–4 weeks
3 19%
Over a month
4 25%

How the animals did

Still unwell when reported
5 11%
Died
27 60%
Euthanised
7 16%
Not known
6 13%

Problems reported at the same time

Age of the animals

Under 1 year
0
1–3 years
5
4–7 years
11
8–11 years
19
12+ years
7

About this medicine

Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs).

Products with this ingredient include ProHeart 6, ProHeart 12. 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 Moxidectin cause heart failure in dogs?
45 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 7 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).

Heart failure with similar medicines

All reported side effects of Moxidectin in dogs · Medicines most reported with heart failure