Neurological signs after Ivermectin (Heartgard) in dogs

86 reports to the FDA describe neurological signs in dogs given Ivermectin. That is 0.7% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

86Reports

42%Marked serious

38%Recovered

15%Died or euthanised

55 daysTypical onset

How soon it started

Same day

7 19%

1–2 days

2 5.6%

3–7 days

2 5.6%

1–4 weeks

5 14%

Over a month

20 56%

How the animals did

Recovered

29 34%

Recovered with lasting effects

4 4.7%

Still unwell when reported

10 12%

Died

10 12%

Euthanised

3 3.5%

Not known

30 35%

Problems reported at the same time

Wobbliness (ataxia)

20 23%

Eye or vision problems

18 21%

16 19%

14 16%

14 16%

13 15%

12 14%

11 13%

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 neurological signs in dogs?: 86 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 55 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).

Neurological signs with similar medicines

Neurological signs after Ivermectin + Pyrantel (Heartgard Plus) 165 reports · 0.1% of its reports
Neurological signs after Milbemycin Oxime + Spinosad (Trifexis) 325 reports · 0.3% of its reports
Neurological signs after Moxidectin (ProHeart 6) 139 reports · 0.3% of its reports
Neurological signs after Milbemycin Oxime + Praziquantel (Interceptor Plus) 41 reports · 0.1% of its reports
Neurological signs after Milbemycin Oxime (Interceptor) 39 reports · 0.1% of its reports
Neurological signs after Selamectin (Revolution) 69 reports · 0.2% of its reports

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