Eosinopenia after Moxidectin (ProHeart 6) in dogs

The FDA has received 63 reports of eosinopenia in dogs after Moxidectin. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

63Reports
68%Marked serious
6.3%Recovered
24%Died or euthanised
4 daysTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
18 37%
1–2 days
5 10%
3–7 days
11 22%
1–4 weeks
5 10%
Over a month
10 20%

How the animals did

Recovered
3 4.8%
Recovered with lasting effects
1 1.6%
Still unwell when reported
37 59%
Died
9 14%
Euthanised
6 9.5%
Not known
7 11%

Problems reported at the same time

Age of the animals

Under 1 year
1
1–3 years
22
4–7 years
24
8–11 years
14
12+ years
2

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 eosinopenia in dogs?
63 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 4 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).

Eosinopenia with similar medicines

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