Neutropenia after Moxidectin (ProHeart 6) in dogs

90 reports to the FDA describe neutropenia in dogs given Moxidectin. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

90Reports
56%Marked serious
4.4%Recovered
28%Died or euthanised
4 daysTypical onset
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How soon it started

Same day
19 28%
1–2 days
13 19%
3–7 days
10 15%
1–4 weeks
10 15%
Over a month
15 22%

How the animals did

Recovered
4 4.4%
Still unwell when reported
45 50%
Died
11 12%
Euthanised
14 16%
Not known
16 18%

Problems reported at the same time

Lethargy
55 61%
Leucopenia
48 53%
Blood problems
46 51%
Loss of appetite
40 44%
Liver problems
39 43%
Vomiting
32 36%
Fever
28 31%
Death
25 28%

Age of the animals

Under 1 year
2
1–3 years
37
4–7 years
31
8–11 years
15
12+ years
5

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 neutropenia in dogs?
90 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).

Neutropenia with similar medicines

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