Drinking a lot after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 118 reports of drinking a lot in dogs after 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.

118Reports
48%Marked serious
36%Recovered
7.6%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
30 37%
1–2 days
16 20%
3–7 days
4 4.9%
1–4 weeks
11 14%
Over a month
20 25%

How the animals did

Recovered
41 35%
Recovered with lasting effects
1 0.8%
Still unwell when reported
16 14%
Died
5 4.2%
Euthanised
4 3.4%
Not known
51 43%

Problems reported at the same time

Age of the animals

Under 1 year
14
1–3 years
33
4–7 years
26
8–11 years
26
12+ years
16

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 drinking a lot in dogs?
118 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).

Drinking a lot with similar medicines

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with drinking a lot