Anxiety after Ivermectin (Heartgard) in dogs

75 reports to the FDA describe anxiety in dogs given Ivermectin. That is 0.6% of all reports for this medicine, compared with 0.5% across reports for all dog medicines.

75Reports
47%Marked serious
43%Recovered
6.7%Died or euthanised
32 daysTypical onset
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How soon it started

Same day
10 23%
1–2 days
5 11%
3–7 days
3 6.8%
1–4 weeks
2 4.5%
Over a month
24 55%

How the animals did

Recovered
28 37%
Recovered with lasting effects
4 5.3%
Still unwell when reported
19 25%
Died
1 1.3%
Euthanised
4 5.3%
Not known
19 25%

Problems reported at the same time

Tremors
21 28%
Behaviour change
20 27%
Breathing problems
17 23%
Vomiting
16 21%
Restlessness or agitation
12 16%
Loss of appetite
12 16%
Weakness
11 15%
Seizures
10 13%

Age of the animals

Under 1 year
6
1–3 years
32
4–7 years
11
8–11 years
15
12+ years
9

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 anxiety in dogs?
75 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 32 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).

Anxiety with similar medicines

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