Leucocytosis after Moxidectin (ProHeart 6) in dogs

773 reports to the FDA describe leucocytosis in dogs given Moxidectin. That is 1.5% of all reports for this medicine, compared with 1.0% across reports for all dog medicines.

773Reports

39%Marked serious

3.8%Recovered

35%Died or euthanised

2 daysTypical onset

How soon it started

Same day

119 30%

1–2 days

89 23%

3–7 days

66 17%

1–4 weeks

57 15%

Over a month

60 15%

How the animals did

Recovered

29 3.8%

Still unwell when reported

260 34%

Died

186 24%

Euthanised

81 10%

Not known

217 28%

Problems reported at the same time

416 54%

405 52%

367 47%

317 41%

304 39%

266 34%

255 33%

207 27%

Age of the animals

Under 1 year

1–3 years

229

4–7 years

239

8–11 years

202

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 leucocytosis in dogs?: 773 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).

Leucocytosis with similar medicines

Leucocytosis after Ivermectin + Pyrantel (Heartgard Plus) 401 reports · 0.3% of its reports
Leucocytosis after Milbemycin Oxime + Spinosad (Trifexis) 474 reports · 0.4% of its reports
Leucocytosis after Milbemycin Oxime + Praziquantel (Interceptor Plus) 136 reports · 0.4% of its reports
Leucocytosis after Milbemycin Oxime (Interceptor) 134 reports · 0.5% of its reports
Leucocytosis after Selamectin (Revolution) 172 reports · 0.6% of its reports
Leucocytosis after Ivermectin (Heartgard) 109 reports · 0.9% of its reports
Leucocytosis after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 22 reports · 0.3% of its reports

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