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

The FDA has received 76 reports of decreased packed cell volume (pcv) in dogs after Moxidectin. That is 0.2% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

76Reports

88%Marked serious

3.9%Recovered

41%Died or euthanised

2 daysTypical onset

How soon it started

Same day

20 27%

1–2 days

18 24%

3–7 days

11 15%

1–4 weeks

9 12%

Over a month

16 22%

How the animals did

Recovered

3 3.9%

Still unwell when reported

41 54%

Died

9 12%

Euthanised

22 29%

Not known

1 1.3%

Problems reported at the same time

51 67%

47 62%

40 53%

36 47%

31 41%

28 37%

23 30%

21 28%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 decreased packed cell volume (pcv) in dogs?: 76 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 2 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).

Decreased packed cell volume (pcv) with similar medicines

Decreased packed cell volume (pcv) after Ivermectin + Pyrantel (Heartgard Plus) 100 reports · 0.1% of its reports
Decreased packed cell volume (pcv) after Milbemycin Oxime + Spinosad (Trifexis) 40 reports · 0.0% of its reports
Decreased packed cell volume (pcv) after Milbemycin Oxime + Praziquantel (Interceptor Plus) 25 reports · 0.1% of its reports
Decreased packed cell volume (pcv) after Ivermectin (Heartgard) 24 reports · 0.2% of its reports

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