Drug dose administration interval too short after Ivermectin + Pyrantel (Heartgard Plus) in dogs

132 reports to the FDA describe drug dose administration interval too short in dogs given Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

132Reports
36%Marked serious
22%Recovered
0.0%Died or euthanised
16 daysTypical onset
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How soon it started

Same day
8 11%
1–2 days
11 15%
3–7 days
9 13%
1–4 weeks
26 36%
Over a month
18 25%

How the animals did

Recovered
21 16%
Recovered with lasting effects
8 6.1%
Still unwell when reported
29 22%
Not known
74 56%

Problems reported at the same time

Age of the animals

Under 1 year
32
1–3 years
45
4–7 years
26
8–11 years
15
12+ years
8

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 drug dose administration interval too short in dogs?
132 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 16 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).

Drug dose administration interval too short with similar medicines

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with drug dose administration interval too short