Restlessness or agitation after Ivermectin (Heartgard) in cats

The FDA has received 22 reports of restlessness or agitation in cats after Ivermectin. That is 2.3% of all reports for this medicine, compared with 4.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

22Reports

18%Marked serious

27%Recovered

4.5%Died or euthanised

–Typical onset

How the animals did

Recovered

2 9.1%

Recovered with lasting effects

4 18%

Died

1 4.5%

Not known

15 68%

Problems reported at the same time

Eye or vision problems

7 32%

6 27%

5 23%

5 23%

4 18%

4 18%

4 18%

4 18%

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 restlessness or agitation in cats?: 22 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).

Restlessness or agitation with similar medicines

Restlessness or agitation after Selamectin (Revolution) 416 reports · 1.9% of its reports
Restlessness or agitation after Eprinomectin + Esafoxolaner + Praziquantel (NexGard Combo) 127 reports · 3.9% of its reports

All reported side effects of Ivermectin in cats · Medicines most reported with restlessness or agitation