Increased packed cell volume (pcv) after Moxidectin (ProHeart 6) in dogs

77 reports to the FDA describe increased packed cell volume (pcv) in dogs given Moxidectin. That is 0.2% 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.

77Reports
69%Marked serious
18%Recovered
9.1%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
42 58%
1–2 days
15 21%
3–7 days
3 4.2%
1–4 weeks
6 8.3%
Over a month
6 8.3%

How the animals did

Recovered
14 18%
Still unwell when reported
50 65%
Died
2 2.6%
Euthanised
5 6.5%
Not known
6 7.8%

Problems reported at the same time

Age of the animals

Under 1 year
0
1–3 years
33
4–7 years
28
8–11 years
13
12+ years
3

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 increased packed cell volume (pcv) in dogs?
77 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 the same 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).

Increased packed cell volume (pcv) with similar medicines

All reported side effects of Moxidectin in dogs · Medicines most reported with increased packed cell volume (pcv)