Staring after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 101 reports of staring in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported less often than average with this medicine.

101Reports
49%Marked serious
43%Recovered
8.9%Died or euthanised
7 daysTypical onset
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How soon it started

Same day
17 25%
1–2 days
12 18%
3–7 days
9 13%
1–4 weeks
19 28%
Over a month
11 16%

How the animals did

Recovered
43 43%
Still unwell when reported
12 12%
Died
6 5.9%
Euthanised
3 3.0%
Not known
37 37%

Problems reported at the same time

Age of the animals

Under 1 year
9
1–3 years
31
4–7 years
28
8–11 years
18
12+ years
12

About this medicine

Ivermectin prevents heartworm disease (monthly). Pyrantel treats roundworms and hookworms.

Products with this combination include Heartgard Plus, Tri-Heart Plus, Iverhart Plus. 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 + Pyrantel cause staring in dogs?
101 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 7 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).

Staring with similar medicines

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with staring