Collapse after Ivermectin (Heartgard) in dogs

109 reports to the FDA describe collapse in dogs given Ivermectin. That is 0.9% of all reports for this medicine, compared with 0.9% across reports for all dog medicines.

109Reports

56%Marked serious

22%Recovered

18%Died or euthanised

28 daysTypical onset

How soon it started

Same day

14 25%

1–2 days

2 3.5%

3–7 days

2 3.5%

1–4 weeks

11 19%

Over a month

28 49%

How the animals did

Recovered

21 19%

Recovered with lasting effects

3 2.8%

Still unwell when reported

21 19%

Died

11 10%

Euthanised

9 8.3%

Not known

44 40%

Problems reported at the same time

34 31%

26 24%

23 21%

19 17%

19 17%

18 17%

17 16%

16 15%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

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 collapse in dogs?: 109 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 28 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).

Collapse with similar medicines

Collapse after Ivermectin + Pyrantel (Heartgard Plus) 432 reports · 0.3% of its reports
Collapse after Milbemycin Oxime + Spinosad (Trifexis) 471 reports · 0.4% of its reports
Collapse after Moxidectin (ProHeart 6) 1,511 reports · 3.0% of its reports
Collapse after Milbemycin Oxime + Praziquantel (Interceptor Plus) 153 reports · 0.5% of its reports
Collapse after Milbemycin Oxime (Interceptor) 163 reports · 0.5% of its reports
Collapse after Selamectin (Revolution) 115 reports · 0.4% of its reports
Collapse after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 60 reports · 0.7% of its reports

All reported side effects of Ivermectin in dogs · Medicines most reported with collapse