Medication error after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 135 reports of medication error in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported less often than average with this medicine.

135Reports
25%Marked serious
61%Recovered
3.0%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
49 67%
1–2 days
5 6.8%
3–7 days
5 6.8%
1–4 weeks
3 4.1%
Over a month
11 15%

How the animals did

Recovered
83 61%
Still unwell when reported
38 28%
Died
2 1.5%
Euthanised
2 1.5%
Not known
10 7.4%

Problems reported at the same time

Age of the animals

Under 1 year
15
1–3 years
41
4–7 years
22
8–11 years
25
12+ years
7

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 medication error in dogs?
135 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 the same 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).

Medication error with similar medicines

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