Increased heart rate after Moxidectin (ProHeart 6) in dogs

The FDA has received 77 reports of increased heart rate in dogs after Moxidectin. That is 0.2% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

77Reports

83%Marked serious

42%Recovered

3.9%Died or euthanised

Same dayTypical onset

How soon it started

Same day

66 87%

1–2 days

3 3.9%

3–7 days

3 3.9%

1–4 weeks

2 2.6%

Over a month

2 2.6%

How the animals did

Recovered

32 42%

Still unwell when reported

39 51%

Died

2 2.6%

Euthanised

1 1.3%

Not known

3 3.9%

Problems reported at the same time

57 74%

54 70%

34 44%

27 35%

20 26%

19 25%

17 22%

15 19%

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 increased heart rate 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 heart rate with similar medicines

Increased heart rate after Ivermectin + Pyrantel (Heartgard Plus) 53 reports · 0.0% of its reports
Increased heart rate after Milbemycin Oxime + Spinosad (Trifexis) 208 reports · 0.2% of its reports
Increased heart rate after Milbemycin Oxime + Praziquantel (Interceptor Plus) 64 reports · 0.2% of its reports
Increased heart rate after Ivermectin (Heartgard) 21 reports · 0.2% of its reports
Increased heart rate after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 32 reports · 0.4% of its reports

All reported side effects of Moxidectin in dogs · Medicines most reported with increased heart rate