Abnormal movement after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 68 reports of abnormal movement in dogs after Ivermectin + Pyrantel. That is 0.0% 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.

68Reports
62%Marked serious
43%Recovered
7.4%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
17 40%
1–2 days
9 21%
3–7 days
1 2.3%
1–4 weeks
3 7.0%
Over a month
13 30%

How the animals did

Recovered
29 43%
Still unwell when reported
7 10%
Died
2 2.9%
Euthanised
3 4.4%
Not known
27 40%

Problems reported at the same time

Age of the animals

Under 1 year
4
1–3 years
22
4–7 years
23
8–11 years
15
12+ years
2

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 abnormal movement in dogs?
68 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 1 day 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).

Abnormal movement with similar medicines

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