Monocytosis after Moxidectin (ProHeart 6) in dogs

177 reports to the FDA describe monocytosis in dogs given Moxidectin. That is 0.3% of all reports for this medicine, compared with 0.3% across reports for all dog medicines.

177Reports

49%Marked serious

5.6%Recovered

38%Died or euthanised

3 daysTypical onset

How soon it started

Same day

22 21%

1–2 days

26 25%

3–7 days

20 19%

1–4 weeks

18 17%

Over a month

20 19%

How the animals did

Recovered

10 5.6%

Still unwell when reported

64 36%

Died

44 25%

Euthanised

24 14%

Not known

35 20%

Problems reported at the same time

116 66%

112 63%

108 61%

102 58%

99 56%

89 50%

79 45%

67 38%

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 monocytosis in dogs?: 177 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 3 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).

Monocytosis with similar medicines

Monocytosis after Ivermectin + Pyrantel (Heartgard Plus) 185 reports · 0.1% of its reports
Monocytosis after Milbemycin Oxime + Spinosad (Trifexis) 96 reports · 0.1% of its reports
Monocytosis after Milbemycin Oxime + Praziquantel (Interceptor Plus) 76 reports · 0.2% of its reports
Monocytosis after Milbemycin Oxime (Interceptor) 29 reports · 0.1% of its reports
Monocytosis after Selamectin (Revolution) 36 reports · 0.1% of its reports
Monocytosis after Ivermectin (Heartgard) 31 reports · 0.3% of its reports

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