Fixed pupil after Ivermectin (Heartgard) in dogs

The FDA has received 41 reports of fixed pupil in dogs after Ivermectin. That is 0.3% of all reports for this medicine, compared with 0.0% across reports for all dog medicines, so it is reported unusually often with this medicine.

41Reports

12%Marked serious

9.8%Recovered

9.8%Died or euthanised

–Typical onset

How the animals did

Recovered

4 9.8%

Died

4 9.8%

Not known

33 80%

Problems reported at the same time

Eye or vision problems

33 80%

19 46%

14 34%

11 27%

11 27%

8 20%

7 17%

5 12%

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 fixed pupil in dogs?: 41 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.
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).

Fixed pupil with similar medicines

Fixed pupil after Moxidectin (ProHeart 6) 32 reports · 0.1% of its reports

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