Systemic disorder after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 136 reports of systemic disorder 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.

136Reports

75%Marked serious

26%Recovered

10%Died or euthanised

30 daysTypical onset

How soon it started

Same day

16 26%

1–2 days

6 9.7%

3–7 days

1 1.6%

1–4 weeks

9 15%

Over a month

30 48%

How the animals did

Recovered

28 21%

Recovered with lasting effects

8 5.9%

Still unwell when reported

13 9.6%

Died

11 8.1%

Euthanised

3 2.2%

Not known

73 54%

Problems reported at the same time

37 27%

30 22%

26 19%

24 18%

Didn't prevent heartworm

19 14%

Death

14 10%

Digestive tract disorder

13 9.6%

Didn't work as expected

12 8.8%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 systemic disorder in dogs?: 136 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 30 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).

Systemic disorder with similar medicines

Systemic disorder after Milbemycin Oxime + Spinosad (Trifexis) 404 reports · 0.3% of its reports
Systemic disorder after Moxidectin (ProHeart 6) 123 reports · 0.2% of its reports
Systemic disorder after Milbemycin Oxime + Praziquantel (Interceptor Plus) 21 reports · 0.1% of its reports
Systemic disorder after Milbemycin Oxime (Interceptor) 26 reports · 0.1% of its reports
Systemic disorder after Selamectin (Revolution) 76 reports · 0.3% of its reports
Systemic disorder after Ivermectin (Heartgard) 32 reports · 0.3% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with systemic disorder