Elevated temperature after Ivermectin (Heartgard) in dogs

The FDA has received 27 reports of elevated temperature in dogs after Ivermectin. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

27Reports
56%Marked serious
56%Recovered
3.7%Died or euthanised
27 daysTypical onset
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How soon it started

Same day
7 32%
1–2 days
0 0.0%
3–7 days
2 9.1%
1–4 weeks
3 14%
Over a month
10 45%

How the animals did

Recovered
12 44%
Recovered with lasting effects
3 11%
Still unwell when reported
4 15%
Euthanised
1 3.7%
Not known
7 26%

Problems reported at the same time

Age of the animals

Under 1 year
6
1–3 years
9
4–7 years
7
8–11 years
4
12+ years
1

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 elevated temperature in dogs?
27 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 27 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).

Elevated temperature with similar medicines

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