Hypothermia after Ivermectin (Heartgard) in cats

42 reports to the FDA describe hypothermia in cats given Ivermectin. That is 4.4% of all reports for this medicine, compared with 1.2% across reports for all cat medicines, so it is reported unusually often with this medicine.

42Reports

12%Marked serious

4.8%Recovered

29%Died or euthanised

–Typical onset

How the animals did

Recovered

2 4.8%

Died

11 26%

Euthanised

1 2.4%

Not known

28 67%

Problems reported at the same time

Wobbliness (ataxia)

15 36%

Eye or vision problems

13 31%

Lethargy

13 31%

Death

12 29%

Loss of consciousness

9 21%

Hyperaesthesia

9 21%

Recumbency

8 19%

Unresponsive

7 17%

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 hypothermia in cats?: 42 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).

Hypothermia with similar medicines

Hypothermia after Selamectin (Revolution) 181 reports · 0.8% of its reports
Hypothermia after Eprinomectin + Esafoxolaner + Praziquantel (NexGard Combo) 56 reports · 1.7% of its reports

All reported side effects of Ivermectin in cats · Medicines most reported with hypothermia