Liver problems after Moxidectin (ProHeart 6) in dogs

The FDA has received 2,025 reports of liver problems in dogs after Moxidectin. That is 4.0% of all reports for this medicine, compared with 4.6% across reports for all dog medicines.

2,025Reports

48%Marked serious

7.8%Recovered

24%Died or euthanised

1 daysTypical onset

How soon it started

Same day

486 40%

1–2 days

207 17%

3–7 days

162 13%

1–4 weeks

151 12%

Over a month

216 18%

How the animals did

Recovered

157 7.8%

Recovered with lasting effects

1 0.0%

Still unwell when reported

865 43%

Died

332 16%

Euthanised

164 8.1%

Not known

506 25%

Problems reported at the same time

944 47%

881 44%

736 36%

520 26%

496 24%

482 24%

422 21%

405 20%

Age of the animals

Under 1 year

1–3 years

611

4–7 years

608

8–11 years

499

12+ years

210

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 liver problems in dogs?: 2,025 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).

Liver problems with similar medicines

Liver problems after Ivermectin + Pyrantel (Heartgard Plus) 1,518 reports · 1.0% of its reports
Liver problems after Milbemycin Oxime + Spinosad (Trifexis) 2,221 reports · 1.7% of its reports
Liver problems after Milbemycin Oxime + Praziquantel (Interceptor Plus) 534 reports · 1.7% of its reports
Liver problems after Milbemycin Oxime (Interceptor) 531 reports · 1.8% of its reports
Liver problems after Selamectin (Revolution) 560 reports · 1.9% of its reports
Liver problems after Ivermectin (Heartgard) 369 reports · 3.1% of its reports
Liver problems after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 149 reports · 1.7% of its reports
Liver problems after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 63 reports · 5.4% of its reports

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