Flaking skin after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 108 reports of flaking skin 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.

108Reports
72%Marked serious
18%Recovered
3.7%Died or euthanised
64 daysTypical onset
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How soon it started

Same day
6 9.4%
1–2 days
4 6.3%
3–7 days
4 6.3%
1–4 weeks
11 17%
Over a month
39 61%

How the animals did

Recovered
17 16%
Recovered with lasting effects
2 1.9%
Still unwell when reported
11 10%
Died
2 1.9%
Euthanised
2 1.9%
Not known
74 69%

Problems reported at the same time

Age of the animals

Under 1 year
5
1–3 years
24
4–7 years
36
8–11 years
32
12+ years
9

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 flaking skin in dogs?
108 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 64 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).

Flaking skin with similar medicines

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