Liver problems after Ivermectin (Heartgard) in dogs

369 reports to the FDA describe liver problems in dogs given Ivermectin. That is 3.1% of all reports for this medicine, compared with 4.6% across reports for all dog medicines.

369Reports

55%Marked serious

16%Recovered

19%Died or euthanised

59 daysTypical onset

How soon it started

Same day

22 10%

1–2 days

20 9.5%

3–7 days

18 8.5%

1–4 weeks

22 10%

Over a month

129 61%

How the animals did

Recovered

33 8.9%

Recovered with lasting effects

26 7.0%

Still unwell when reported

129 35%

Died

21 5.7%

Euthanised

49 13%

Not known

111 30%

Problems reported at the same time

138 37%

122 33%

119 32%

73 20%

69 19%

65 18%

45 12%

43 12%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

122

12+ years

About this medicine

Ivermectin prevents heartworm disease (monthly).

Products with this ingredient include Heartgard. 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 Ivermectin cause liver problems in dogs?: 369 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 59 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).

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 Moxidectin (ProHeart 6) 2,025 reports · 4.0% 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 + 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 Ivermectin in dogs · Medicines most reported with liver problems