Blood in stool after Moxidectin (ProHeart 6) in dogs

The FDA has received 185 reports of blood in stool in dogs after Moxidectin. That is 0.4% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported less often than average with this medicine.

185Reports

35%Marked serious

9.7%Recovered

26%Died or euthanised

1 daysTypical onset

How soon it started

Same day

44 50%

1–2 days

15 17%

3–7 days

8 9.1%

1–4 weeks

11 13%

Over a month

10 11%

How the animals did

Recovered

18 9.7%

Still unwell when reported

59 32%

Died

41 22%

Euthanised

8 4.3%

Not known

59 32%

Problems reported at the same time

102 55%

71 38%

63 34%

61 33%

57 31%

56 30%

48 26%

38 21%

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 blood in stool in dogs?: 185 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 1 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).

Blood in stool with similar medicines

Blood in stool after Ivermectin + Pyrantel (Heartgard Plus) 196 reports · 0.1% of its reports
Blood in stool after Milbemycin Oxime + Spinosad (Trifexis) 79 reports · 0.1% of its reports
Blood in stool after Milbemycin Oxime + Praziquantel (Interceptor Plus) 38 reports · 0.1% of its reports
Blood in stool after Milbemycin Oxime (Interceptor) 148 reports · 0.5% of its reports
Blood in stool after Selamectin (Revolution) 109 reports · 0.4% of its reports
Blood in stool after Ivermectin (Heartgard) 31 reports · 0.3% of its reports

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