Didn't stop fleas after Moxidectin (ProHeart 6) in dogs

70 reports to the FDA describe didn't stop fleas in dogs given Moxidectin. That is 0.1% of all reports for this medicine, compared with 6.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

70Reports

16%Marked serious

7.1%Recovered

1.4%Died or euthanised

25 daysTypical onset

How soon it started

Same day

7 22%

1–2 days

0 0.0%

3–7 days

0 0.0%

1–4 weeks

11 34%

Over a month

14 44%

How the animals did

Recovered

4 5.7%

Recovered with lasting effects

1 1.4%

Still unwell when reported

21 30%

Died

1 1.4%

Not known

43 61%

Problems reported at the same time

Didn't work as expected

16 23%

8 11%

6 8.6%

4 5.7%

3 4.3%

3 4.3%

3 4.3%

Unpalatable

3 4.3%

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 didn't stop fleas in dogs?: 70 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 25 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).

Didn't stop fleas with similar medicines

Didn't stop fleas after Ivermectin + Pyrantel (Heartgard Plus) 483 reports · 0.3% of its reports
Didn't stop fleas after Milbemycin Oxime + Spinosad (Trifexis) 8,717 reports · 6.7% of its reports
Didn't stop fleas after Milbemycin Oxime + Praziquantel (Interceptor Plus) 171 reports · 0.5% of its reports
Didn't stop fleas after Milbemycin Oxime (Interceptor) 118 reports · 0.4% of its reports
Didn't stop fleas after Selamectin (Revolution) 3,379 reports · 11% of its reports
Didn't stop fleas after Ivermectin (Heartgard) 451 reports · 3.8% of its reports
Didn't stop fleas after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 38 reports · 0.4% of its reports
Didn't stop fleas after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 21 reports · 1.8% of its reports

All reported side effects of Moxidectin in dogs · Medicines most reported with didn't stop fleas