Unable to stand after Ivermectin + Pyrantel (Heartgard Plus) in dogs

The FDA has received 198 reports of unable to stand in dogs after Ivermectin + Pyrantel. That is 0.1% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

198Reports

70%Marked serious

38%Recovered

20%Died or euthanised

2 daysTypical onset

How soon it started

Same day

43 35%

1–2 days

23 19%

3–7 days

12 9.8%

1–4 weeks

17 14%

Over a month

28 23%

How the animals did

Recovered

75 38%

Recovered with lasting effects

1 0.5%

Still unwell when reported

20 10%

Died

13 6.6%

Euthanised

27 14%

Not known

62 31%

Problems reported at the same time

71 36%

68 34%

48 24%

43 22%

39 20%

39 20%

31 16%

27 14%

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 unable to stand in dogs?: 198 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 2 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).

Unable to stand with similar medicines

Unable to stand after Milbemycin Oxime + Spinosad (Trifexis) 419 reports · 0.3% of its reports
Unable to stand after Moxidectin (ProHeart 6) 132 reports · 0.3% of its reports
Unable to stand after Milbemycin Oxime + Praziquantel (Interceptor Plus) 76 reports · 0.2% of its reports
Unable to stand after Milbemycin Oxime (Interceptor) 28 reports · 0.1% of its reports
Unable to stand after Selamectin (Revolution) 39 reports · 0.1% of its reports
Unable to stand after Ivermectin (Heartgard) 67 reports · 0.6% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with unable to stand